Method for controlling uplink power in wireless communication system and device therefor

ABSTRACT

The present invention relates to a wireless communication system and, more specifically, provides a method for controlling uplink power and a device therefor. The method whereby user equipment controls uplink transmission power in a wireless communication system according to one embodiment of the present invention may comprise the steps of: receiving configuration information regarding a plurality of subframe sets from a base station; receiving, in the subframe index j, transmission power control (TPC) information from the base station; and determining transmission power for an uplink channel in the subframe index i on the basis of the TPC information. The TPC information may be applied to a power control process related to a first subframe set, to which the subframe index i belongs, among the plurality of subframe sets.

TECHNICAL FIELD

The present invention relates to a wireless communication system and,more particularly, to a method for controlling uplink power and a devicetherefor.

BACKGROUND ART

A structure of an LTE system which is an example of a wirelesscommunication system to which the present invention may be applied willbe described with reference to FIG. 1.

FIG. 1 illustrates a schematic structure a network structure of anevolved universal mobile telecommunication system (E-UMTS). An E-UMTSsystem is an evolved version of the UMTS system and basicstandardization thereof is in progress under the 3rd GenerationPartnership Project (3GPP). The E-UMTS is also referred to as a LongTerm Evolution (LTE) system. For details of the technical specificationsof the UMTS and E-UMTS, refer to Release 7 and Release 8 of “3rdGeneration Partnership Project; Technical Specification Group RadioAccess Network”.

Referring to FIG. 1, the E-UMTS includes a User Equipment (UE), basestations (or eNBs or eNode Bs), and an Access Gateway (AG) which islocated at an end of a network (E-UTRAN) and which is connected to anexternal network. Generally, an eNB can simultaneously transmit multipledata streams for a broadcast service, a multicast service and/or aunicast service.

One or more cells may exist for one BS. The cell provides a downlink oruplink transmission service to several UEs using any one of bandwidthsof 1.4, 3, 5, 10, 15 and 20 MHz. Different cells may be set to providedifferent bandwidths. A BS controls data transmission or reception to orfrom a plurality of UEs. The BS transmits downlink schedulinginformation to a UE with respect to downlink (DL) data so as to informthe UE of time/frequency domain, coding, data size, Hybrid AutomaticRepeat and reQuest (HARQ) associated information of data to betransmitted, or the like. The BS transmits uplink scheduling informationto a UE with respect to uplink (UL) data so as to inform the UE oftime/frequency domain, coding, data size, HARQ associated informationused by the UE, or the like. An interface for transmitting user trafficor control traffic can be used between BSs. A Core Network (CN) mayinclude the AG, a network node for user registration of the UE, or thelike. The AG manages mobility of a UE on a Tracking Area (TA) basis. OneTA includes a plurality of cells.

Wireless communication technology has been developed to reach the LTEbased on Wideband Code Division Multiple Access (WCDMA), but demands andexpectations of users and providers have continuously increased. Inaddition, since other aspects of wireless access technology continue toevolve, new advances are required to remain competitive in the future.There is a need for reduction in cost per bit, service availabilityincrease, the use of a flexible frequency band, a simple structure andan open type interface, appropriate power consumption of a UE, etc.

Recently, 3GPP has been proceeding with standardization of a successorto LTE. In this specification, the successor will be referred to as“LTE-A”. LTE-A is designed to support a wideband covering a maximumfrequency of 100 MHz. To this end, a carrier aggregation (CA) techniqueis employed to achieve wideband using a plurality of frequency blocks.CA uses a plurality of frequency blocks as one large logical frequencyband in order to use a wider frequency band. The bandwidth of afrequency block may be defined based on the bandwidth of the systemblock used in the LTE system. Each frequency block may be referred to asa component carrier (CC) or a cell.

In addition, in the LTE system, a duplex operation of dividing allavailable resources into DL resources (i.e., resources which a basestation uses to transmit a signal to a UE) and UL resources (i.e.,resources which the UE uses to transmit a signal to the base station)may be supported. For example, a frequency division duplex (FDD) schemeor a time division duplex (TDD) scheme may be applied. In this way, eachresource may be used either for DL or for UL. In the legacy LTE system,use of each resource is specified through system information.

Recently, a method to dynamically establish DL-UL configuration inperforming a duplex operation is under discussion as an improved methodfor the LTE/LTE-A systems.

DISCLOSURE Technical Problem

An object of the present invention devised to solve the problem lies inan uplink power control method that efficiently supports DL-ULinterference management and traffic adaptation in dynamicallyestablishing DL-UL configuration.

It will be appreciated by persons skilled in the art that the objectsthat could be achieved with the present invention are not limited towhat has been particularly described hereinabove and the above and otherobjects that the present invention could achieve will be more clearlyunderstood from the following detailed description.

Technical Solution

The object of the present invention can be achieved by providing amethod for performing uplink transmit power control by a user equipmentin a wireless communication system, the method including receivingconfiguration information about a plurality of subframe sets from a basestation, receiving transmit power control (TPC) information from thebase station in a subframe #j, and determining a transmit power for anuplink channel in a subframe #i based on the TPC information, whereinthe TPC information is applied to a power control process associatedwith a first subframe set including the subframe #i among the subframesets.

In another aspect of the present invention, provided herein is a methodfor receiving an uplink signal by a base station in a wirelesscommunication system, the method including transmitting configurationinformation about a plurality of subframe sets to a user equipment,transmitting transmit power control (TPC) information to the userequipment in a subframe #j, and receiving the uplink signal from theuser equipment on an uplink channel in a subframe #i, wherein a transmitpower for the uplink channel in the subframe #i is determined based onthe TPC information, wherein the TPC information is applied to a powercontrol process associated with a first subframe set including thesubframe #i among the subframe sets.

In another aspect of the present invention, provided herein is a userequipment for performing uplink transmit power control in a wirelesscommunication system, including a transmission module, a receptionmodule, and a processor, wherein the processor is configured to controlthe reception module to receive configuration information about aplurality of subframe sets from a base station, control the receptionmodule to receive transmit power control (TPC) information from the basestation in a subframe #j, and determine a transmit power for an uplinkchannel in a subframe #i based on the TPC information, wherein the TPCinformation is applied to a power control process associated with afirst subframe set including the subframe #i among the subframe sets.

In another aspect of the present invention, provided herein is a basestation for receiving an uplink signal in a wireless communicationsystem, including a transmission module, a reception module, and aprocessor, wherein the processor is configured to control thetransmission module to transmit configuration information about aplurality of subframe sets to a user equipment, control the transmissionmodule to transmit transmit power control (TPC) information to the userequipment in a subframe #j, control the reception module to receive theuplink signal from the user equipment on an uplink channel in a subframe#i, wherein a transmit power for the uplink channel in the subframe #iis determined based on the TPC information, wherein the TPC informationis applied to a power control process associated with a first subframeset including the subframe #i among the subframe sets.

Embodiments according to the aspects of the present invention mayinclude the following details.

The TPC information may not be applied to a power control processassociated with a second subframe set among the subframe sets.

The TPC information may be contained in downlink control information(DCI) format 0 or DCI format 4 containing uplink grant information forscheduling uplink data transmission in the subframe #i.

The TPC information may be contained in downlink control information(DCI) format 3 or DCI format 3A.

Association between the subframe #j and the subframe #i may bedetermined based on uplink-downlink (UL-DL) configuration informationprovided from the base station.

The UL-DL configuration information may be provided through dynamicsignaling.

The uplink channel may be a physical uplink control channel (PUCCH) orphysical uplink shared channel (PUSCH).

The wireless communication system may be a time division duplex (TDD)system.

It is to be understood that both the foregoing general description andthe following detailed description of the present invention areexemplary and explanatory and are intended to provide furtherexplanation of the invention as claimed.

Advantageous Effects

According to an embodiment of the present invention, an improved powercontrol method for efficiently supporting DL-UL interference managementand traffic adaptation in dynamically establishing DL-UL configurationmay be provided.

The effects that can be obtained from the present invention are notlimited to the aforementioned effects, and other effects may be clearlyunderstood by those skilled in the art from the descriptions givenbelow.

DESCRIPTION OF DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention, illustrate embodiments of the inventionand together with the description serve to explain the principle of theinvention.

FIG. 1 is a schematic diagram showing a network architecture of anEvolved Universal Mobile Telecommunications System (E-UMTS) as anexample of a mobile communication system.

FIG. 2 exemplarily shows a radio frame structure.

FIG. 3 exemplarily shows a resource grid of a downlink slot.

FIG. 4 exemplarily shows a downlink subframe structure and an uplinksubframe structure.

FIGS. 5 and 6 illustrate TDD UL ACK/NACK (UplinkAcknowledgement/Negative Acknowledgement) transmission timing in asingle cell case.

FIGS. 7 and 8 illustrate TDD PUSCH (Physical Uplink Shared Channel)transmission timing in a single cell case.

FIGS. 9 and 10 illustrate TDD DL ACK/NACK transmission timing in asingle cell case.

FIG. 11 illustrates a TDD HARQ (Hybrid Automatic Repeat request) processin a single cell situation.

FIG. 12 illustrates configuration of subframe sets according to anembodiment of the present invention.

FIG. 13 is a flowchart illustrating a method for controlling UL transmitpower according to an embodiment of the present invention.

FIG. 14 is a diagram illustrating a oreferred embodiment of a basestation 10 and a user equipment 20 according to the present invention.

BEST MODE

The following embodiments are achieved by combination of structuralelements and features of the present invention in a predetermined type.Each of the structural elements or features should be consideredselectively unless specified separately. Each of the structural elementsor features may be carried out without being combined with otherstructural elements or features. Also, some structural elements and/orfeatures may be combined with one another to constitute the embodimentsof the present invention. The order of operations described in theembodiments of the present invention may be changed. Some structuralelements or features of one embodiment may be included in anotherembodiment, or may be replaced with corresponding structural elements orfeatures of another embodiment.

In this specification, the embodiments of the present invention havebeen described based on the data transmission and reception between abase station BS and a user equipment UE. In this case, the base stationBS means a terminal node of a network, which performs directcommunication with the user equipment UE. A specific operation which hasbeen described as being performed by the base station may be performedby an upper node of the base station BS as the case may be.

In other words, it will be apparent that various operations performedfor communication with the user equipment UE in the network whichincludes a plurality of network nodes along with the base station may beperformed by the base station BS or network nodes other than the basestation BS. At this time, the base station BS may be replaced with termssuch as a fixed station, Node B, eNode B (eNB), and an access point(AP). A relay node may be replaced with terms such as a relay node (RN)and a relay station (RS). Also, a terminal may be replaced with termssuch as a user equipment (UE), a mobile station (MS), a mobilesubscriber station (MSS), and a subscriber station (SS).

Specific terminologies hereinafter used in the embodiments of thepresent invention are provided to assist understanding of the presentinvention, and various modifications may be made in the specificterminologies within the range that they do not depart from technicalspirits of the present invention.

In some cases, to prevent the concept of the present invention frombeing ambiguous, structures and apparatuses of the known art will beomitted, or will be shown in the form of a block diagram based on mainfunctions of each structure and apparatus. Also, wherever possible, thesame reference numbers will be used throughout the drawings and thespecification to refer to the same or like parts.

The embodiments of the present invention may be supported by standarddocuments disclosed in at least one of wireless access systems, i.e.,IEEE 802 system, 3GPP system, 3GPP LTE system, 3GPP LTE, 3GPP LTE-A(LTE-Advanced) system, and 3GPP2 system. Namely, among the embodimentsof the present invention, apparent steps or parts, which are notdescribed to clarify technical spirits of the present invention, may besupported by the above documents. Also, all terminologies disclosedherein may be described by the above standard documents.

The following technology may be used for various wireless access systemssuch as CDMA (code division multiple access), FDMA (frequency divisionmultiple access), TDMA (time division multiple access), OFDMA(orthogonal frequency division multiple access), and SC-FDMA (singlecarrier frequency division multiple access). The CDMA may be implementedby the radio technology such as universal terrestrial radio access(UTRA) or CDMA2000. The TDMA may be implemented by the radio technologysuch as global system for mobile communications (GSM)/general packetradio service (GPRS)/enhanced data rates for GSM evolution (EDGE). TheOFDMA may be implemented by the radio technology such as IEEE 802.11(Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, and evolved UTRA (E-UTRA).The UTRA is a part of a universal mobile telecommunications system(UMTS). A 3rd generation partnership project long term evolution (3GPPLTE) communication system is a part of an evolved UMTS (E-UMTS) thatuses E-UTRA, and uses OFDMA in a downlink while uses SC-FDMA in anuplink. LTE-advanced (LTE-A) is an evolved version of the 3GPP LTEsystem. WiMAX may be described by the IEEE 802.16e standard(WirelessMAN-OFDMA Reference System) and the advanced IEEE 802.16mstandard (WirelessMAN-OFDMA Advanced system). Although the followingdescription will be based on the 3GPP LTE system and the 3GPP LTE-Asystem to clarify description, it is to be understood that technicalspirits of the present invention are not limited to the 3GPP LTE and the3GPP LTE-A system.

A radio frame structure will now be described with reference to FIG. 2.

In a cellular OFDM wireless packet communication system, anuplink/downlink data packet is transmitted on a eme basis and onesubframe is defined as a predetermined time interval including aplurality of OFDM symbols. 3GPP LTE standard supports a type-1 radioframe structure applicable to frequency division duplex (FDD) and atype-2 radio frame structure applicable to time division duplex (TDD).

FIG. 2( a) illustrates the type-1 radio frame structure. A downlinkradio frame is divided into 10 subframes. Each subframe is furtherdivided into two slots in the time domain. A unit time during which onesubframe is transmitted is defined as transmission time interval (TTI).For example, one subframe may be 1 ms in duration and one slot may be0.5 ms in duration. A slot may include a plurality of orthogonalfrequency division multiplexing (OFDM) symbols in the time domain andincludes a plurality of resource blocks (RBs) in the frequency domain.Because the 3GPP LTE system adopts OFDMA for downlink, an OFDM symbolrepresents one symbol period. An OFDM symbol may be referred to as anSC-FDMA symbol or symbol period. A Resource Block (RB) is a resourceallocation unit including a plurality of contiguous subcarriers in aslot.

The number of OFDM symbols included in one slot depends on cyclic prefix(CP) configuration. CP is divided into an extended CP and a normal CP.For example, when OFDM symbols are configured according to normal CP,the number of OFDM symbols included in one slot may be 7. When the OFDMsymbols are configured according to extended CP, the duration of oneOFDM symbol increases and thus the number of OFDM symbols included inone slot is smaller than the number of OFDM symbols included in one slotwhen the OFDM symbols are configured using the normal CP. In theextended CP case, the number of OFDM symbols included in one slot may be6, for example. When a channel status is unstable, for example, when aUE moves at a high speed, the extended CP can be used to reduceinter-symbol interference.

When the normal CP is used, one slot includes 7 OFDM symbols, and thusone subframe includes 14 OFDM symbols. In this case, up to three OFDMsymbols at the start of each subframe can be allocated to a physicaldownlink control channel (PDCCH) and the other three OFDM symbols can beallocated to a physical downlink shared channel (PDSCH).

FIG. 2( b) illustrates the type-2 radio frame structure. The type-2radio frame includes two half frames each having 5 subframes, a downlinkpilot time slot (DwPTS), a guard period (GP), and an uplink pilot timeslot (UpPTS). Each subframe includes two slots. The DwPTS is used forinitial cell search, synchronization, or channel estimation in a UE,whereas the UpPTS is used for channel estimation in an eNB and uplinktransmission synchronization in a UE. The GP is a period between adownlink and an uplink, for eliminating interference with the uplinkcaused by multi-path delay of a downlink signal. A subframe is composedof two slots irrespective of radio frame type.

The radio frame can be configured differently according to duplex mode.Downlink transmission is discriminated from uplink transmission byfrequency in FDD (Frequency Division Duplex) mode, and thus the radioframe includes only one of a downlink subframe and an uplink subframe ina specific frequency band.

Table 1 shows UL-DL configurations of subframes in a radio frame in theTDD mode.

TABLE 1 Uplink- Downlink- downlink to-Uplink Config- Switch-pointSubframe number uration periodicity 0 1 2 3 4 5 6 7 8 9 0 5 ms D S U U UD S U U U 1 5 ms D S U U D D S U U D 2 5 ms D S U D D D S U D D 3 10 ms D S U U U D D D D D 4 10 ms  D S U U D D D D D D 5 10 ms  D S U D D D DD D D 6 5 ms D S U U U D S U U D

In Table 1, D denotes a downlink subframe, U denotes an uplink subframeand S denotes a special subframe. The special subframe includes DwPTS(Downlink Pilot TimeSlot), GP (Guard Period), and UpPTS (Uplink PilotTimeSlot). DwPTS is a period reserved for downlink transmission andUpPTS is a period reserved for uplink transmission. Table 2 showsspecial subframe configuration.

TABLE 2 Normal cyclic prefix in downlink Extended cyclic prefix indownlink UpPTS UpPTS Special Normal cyclic Extended Normal Extendedsubframe prefix in cyclic prefix DwPTS cyclic prefix cyclic prefixconfig. DwPTS uplink in uplink ee in uplink in uplink 0  6592 · Ts 2192· Ts 2560 · Ts  7680 · Ts 2192 · Ts 2560 · Ts 1 19760 · Ts 20480 · Ts 221952 · Ts 23040 · Ts 3 24144 · Ts 25600 · Ts 4 26336 · Ts  7680 · Ts4384 · Ts 5120 · Ts 5  6592 · Ts 4384 · Ts 5120 · Ts 20480 · Ts 6 19760· Ts 23040 · Ts 7 21952 · Ts — — — 8 24144 · Ts — — —

The aforementioned radio frame structure is purely exemplary and thusthe number of subframes included in a radio frame, the number of slotsincluded in a subframe, or the number of symbols included in a slot mayvary.

FIG. 3 illustrates a resource grid for a downlink slot.

A downlink slot includes 7 OFDM symbols in the time domain and an RBincludes 12 subcarriers in the frequency domain, which does not limitthe scope and spirit of the present invention. For example, a slotincludes 7 OFDM symbols in the case of normal CP, whereas a slotincludes 6 OFDM symbols in the case of extended CP. Each element of theresource grid is referred to as a resource element (RE). An RB includes12×7 REs. The number of RBs in a downlink slot, NDL depends on adownlink transmission bandwidth. An uplink slot may have the samestructure as a downlink slot.

FIG. 4( a) illustrates a downlink subframe structure.

Up to three OFDM symbols at the start of the first slot in a downlinksubframe are used for a control region to which control channels areallocated and the other OFDM symbols of the downlink subframe are usedfor a data region to which a PDSCH is allocated.

Downlink control channels used in 3GPP LTE include a physical controlformat indicator channel (PCFICH), a physical downlink control channel(PDCCH), and a physical hybrid automatic repeat request (ARQ) indicatorchannel (PHICH). The PCFICH is located in the first OFDM symbol of asubframe, carrying information about the number of OFDM symbols used fortransmission of control channels in the subframe. The PHICH delivers aHARQ acknowledgment/negative acknowledgment (ACK/NACK) signal inresponse to an uplink transmission.

Control information carried on the PDCCH is called downlink controlinformation (DCI). The DCI includes uplink resource allocationinformation, downlink resource allocation information or an uplinktransmit (Tx) power control command for an arbitrary UE group. The PDCCHdelivers information about resource allocation and a transport formatfor a Downlink Shared Channel (DL-SCH), resource allocation informationabout an Uplink Shared Channel (UL-SCH), paging information of a PagingChannel (PCH), system information on the DL-SCH, information aboutresource allocation for a higher-layer control message such as a RandomAccess Response transmitted on the PDSCH, a set of transmission powercontrol commands for individual UEs of a UE group, transmission powercontrol information, Voice Over Internet Protocol (VoIP) activationinformation, etc. A plurality of PDCCHs may be transmitted in thecontrol region. A UE may monitor a plurality of PDCCHs.

Information content of DCI formats are as follows.

DCI format 0: Signaling of resource allocation information for physicaluplink shared channel (PUSCH) transmission.

DCI format 1: Signaling of resource allocation information for singlecodeword physical downlink shared channel (PDSCH) transmission.

DCI format 1A: Compact signaling of resource allocation information forsingle codeword PDSCH transmission.

DCI format 1B: Compact signaling of resource allocation information forPDSCH transmission using rank-1 closed loop precoding.

DCI format 1C: Very compact signaling of resource allocation informationfor PDSCH transmission (for, for example, paging or broadcasting ofsystem information.

DCI format 1D: Compact signaling of resource allocation information forPDSCH transmission using multi-user MIMO (Multiple Input MultipleOutput).

DCI format 2: Signaling of PDSCH resource allocation information for aclosed loop MIMO operation.

DCI format 2A: Signaling of PDSCH resource allocation information for anopen loop MIMO operation.

DCI format 2B: Signaling of resource allocation information for duallayer transmission using a demodulation reference signal (DMRS).

DCI format 2C: Signaling of resource allocation information for closedloop spatial multiplexing transmission using a DMRS.

DCI format 2D: Signaling of resource allocation information forsupporting a Coordinated Multipoint (CoMP) operation.

DCI format 3/3A: Signaling for a PUCCH/PUSCH power control commandcontaining 2-bit or 1-bit power adjustment information.

DCI format 4: Signaling for uplink scheduling for one uplink cellsupporting the multi-antenna port transmission mode.

A PDCCH is formed by aggregation of one or more consecutive ControlChannel Elements (CCEs). A CCE is a logical allocation unit used toprovide a PDCCH at a coding rate based on the state of a radio channel.A CCE corresponds to a plurality of REs. The format of a PDCCH and thenumber of available bits for the PDCCH are determined according to thecorrelation between the number of CCEs and a coding rate provided by theCCEs.

An eNB determines the PDCCH format according to DCI transmitted to a UEand adds a Cyclic Redundancy Check (CRC) to control information. The CRCis masked by an Identifier (ID) known as a Radio Network TemporaryIdentifier (RNTI) according to the owner or usage of the PDCCH. If thePDCCH is directed to a specific UE, its CRC may be masked by a cell-RNTI(C-RNTI) of the UE. If the PDCCH carries a paging message, the CRC ofthe PDCCH may be masked by a Paging Indicator Identifier (P-RNTI). Ifthe PDCCH carries system information, particularly, a System InformationBlock (SIB), its CRC may be masked by a system information ID and aSystem Information RNTI (SI-RNTI). To indicate that the PDCCH carries aRandom Access Response in response to a Random Access Preambletransmitted by a UE, its CRC may be masked by a Random Access-RNTI(RA-RNTI).

FIG. 4( b) illustrates an uplink subframe structure.

An uplink subframe may be divided into a control region and a dataregion in the frequency domain. A physical uplink control channel(PUCCH) carrying uplink control information is allocated to the controlregion and a physical uplink shared channel (PUSCH) carrying user datais allocated to the data region. To maintain single carrier property, aUE does not transmit a PUSCH and a PUCCH simultaneously. A PUCCH for aUE is allocated to an RB pair in a subframe. The RBs of the RB pairoccupy different subcarriers in two slots. Thus it is said that the RBpair allocated to the PUCCH is frequency-hopped over a slot boundary.

Hybrid Automatic Repeat Request (HARQ) Operation

As a control method for reception failure of data, the following HARQoperation may be applied. If a data transmitter receives an ACK signalfrom a data receiver after transmitting a packet, the data transmittermay transmit a new packet. If the data transmitter receives a NACKsignal, the previously transmitted packet may be retransmitted. In thiscase, a packet to which encoding is applied according to the function offorward error correction (FEC) may be retransmitted. Accordingly, thedata receiver receives the packet. If the data receiver succeeds indecoding the received packet, it transmits an ACK signal. If the datareceiver fails to decode the packet, it transmits a NACK signal andstores the received packet in the buffer. Then, if the data receiverreceives a retransmitted packet according to the NACK signal, it decodesthe same in combination with the received packet in the buffer. Thereby,the success rate of packet reception may be increased.

The HARQ scheme may be divided into a synchronous HARQ scheme and anasynchronous HARQ scheme according to retransmission timing In thesynchronous HARQ scheme, when initial transmission fails, subsequentretransmission is performed at times determined by the system. Forexample, when retransmission is set to be performed every fourth timeunit (e.g., subframe) after initial transmission fails, informationabout the retransmission time does not need to be additionally announcedto the receiver. Accordingly, if the data transmitter receives a NACKsignal, it retransmits the packet every fourth time until it receives anACK signal. Meanwhile, in the asynchronous HARQ scheme, informationabout the retransmission time is separately scheduled. Accordingly, theretransmission time of the packet corresponding to the NACK signal maychange depending on various conditions such as channel state.

The HARQ scheme may also be divided into an adaptive HARQ scheme and anon-adaptive HARQ scheme according to whether or not the amount ofresources used in performing retransmission is determined inconsideration of the channel state. In the non-adaptive HARQ scheme, theMCS level of a retransmitted packet, the number of resource blocks to beused and the like are maintained as determined in the initialtransmission. For example, if the transmitter uses 8 RBs to transmitdata in implementing initial transmission, it performs retransmissionthereafter using 8 RBs. In the adaptive HARQ scheme, the demodulationscheme for a packet, the number of RBs to be used and the like depend onthe channel sate. For example, even if initial transmission is performedusing 8 RBs, subsequent retransmission may be performed using more thanor less than 8 RBs depending on the channel state.

As described above, in performing data packet transmission through HARQ,the transmitter may transform a data packet into sub-packets of apredetermined size and perform initial transmission and retransmissionin units of sub-packet. The receiver may attempt to decode the datapacket by combining multiple sub-packets.

Multiple sub-packets used for initial transmission and retransmission bythe HARQ scheme are generated from one codeword packet. The generatedsub-packets may be distinguished from each other by the lengths of thesub-packets and the start positions of the sub-packets. Suchdistinguishable sub-packets are called a redundancy version (RV). Thereceiver may receive different RVs and attempt to decode a wholecodeword by combining the RVs. For example, the HARQ operation may beperformed in a manner that decoding is attempted by receivingsub-packets corresponding to a difference between a whole codewordpacket to be received and the previously received sub-packets. Thisoperation may be called a HARQ operation of an incremental redundancy(IR) scheme.

TDD HARQ

A description will be given of TDD signal transmission timing in asingle carrier (or cell) situation with reference to FIGS. 5 to 11.

FIGS. 5 and 6 illustrate PDSCH-UL ACK/NACK timing. Here, UL ACK/NACKmeans ACK/NACK transmitted on uplink, as a response to DL data (e.g.PDSCH).

Referring to FIG. 5, a UE can receive one or more PDSCH signals in M DLsubframes (SFs) (S502_0 to S502_M-1). Each PDSCH signal is used totransmit one or more (e.g. 2) transport blocks (TBs) according totransmission mode. A PDCCH signal indicating SPS (Semi-PersistentScheduling) may also be received in step S502_0 to S502_M-1, which isnot shown. When a PDSCH signal and/or an SPS release PDCCH signal ispresent in the M DL subframes, the UE transmits ACK/NACK through a ULsubframe corresponding to the M DL subframes via processes fortransmitting ACK/NACK (e.g. ACK/NACK (payload) generation, ACK/NACKresource allocation, etc.) (S504). ACK/NACK includes acknowledgementinformation about the PDSCH signal and/or an SPS release PDCCH receivedin step S502_0 to S502_M-1. While ACK/NACK is transmitted through aPUCCH basically, ACK/NACK is transmitted through a PUSCH when a PUSCH istransmitted at ACK/NACK transmission time. Various PUCCH formats shownin Table 3 can be used for ACK/NACK transmission. To reduce the numberof ACK/NACK bits transmitted through a PUCCH format, various methodssuch as ACK/NACK bundling and ACK/NACK channel selection can be used.

As described above, in TDD, ACK/NACK relating to data received in the MDL subframes is transmitted through one UL subframe (i.e. M DL SF(s): 1UL SF) and the relationship therebetween is determined by a DASI(Downlink Association Set Index).

Table 3 shows DASI (K: {k0, k1, . . . , k-1}) defined in LTE(-A). Table3 shows spacing between a UL subframe transmitting ACK/NACK and a DLsubframe relating to the UL subframe. Specifically, when a PDCCH thatindicates PDSCH transmission and/or SPS release is present in a subframen−k (k∈K), the UE transmits ACK/NACK in a subframe n.

TABLE 3 TDD UL-DL Config- Subframe n uration 0 1 2 3 4 5 6 7 8 9 0 — — 6— 4 — — 6 — 4 1 — — 7, 6 4 — — — 7, 6 4 — 2 — — 8, 7, 4, 6 — — — — 8, 7,— — 4, 6 3 — — 7, 6, 11 6, 5 5, 4 — — — — — 4 — — 12, 8, 7, 11 6, 5, — —— — — — 4, 7 5 — — 13, 12, 9, 8, — — — — — — — 7, 5, 4, 11, 6 6 — — 7 75 — — 7 7 —

FIG. 6 illustrates UL ACK/NACK transmission timing when UL-DLconfiguration #1 is configured. In the figure, SF#0 to #9 and SF#10 to#19 respectively correspond to radio frames, and numerals in blocksdenote UL subframes relating to DL subframes. For example, ACK/NACK fora PDSCH of SF#5 is transmitted in SF#5+7(=SF#12) and ACK/NACK for aPDSCH of SF#6 is transmitted in SF#6+6(=SF#12). Accordingly, bothACKs/NACKs for DL signals of SF#5/#6 are transmitted in SF#12.Similarly, ACK/NACK for a PDSCH of SF#14 is transmitted inSF#14+4(=SF#18).

FIGS. 7 and 8 illustrate PHICH grant-PUSCH timing. A PUSCH can betransmitted corresponding to a PDCCH (UL grant) and/or a PHICH (NACK).

Referring to FIG. 7, the UE can receive a PDCCH (UL grant) and/or aPHICH (NACK) through a PDCCH (S702). Here, NACK corresponds to anACK/NACK response to previous PUSCH transmission. In this case, the UEcan initially transmit/retransmit one or more TBs through a PUSCH afterk subframes via processes for PUSCH transmission (e.g. TB coding, TB-CWswiping, PUSCH resource allocation, etc.) (S704). The present embodimentis based on the assumption that a normal HARQ operation in which a PUSCHis transmitted once is performed. In this case, a PHICH and a UL grantcorresponding to PUSCH transmission are present in the same subframe.However, in case of subframe bundling in which a PUSCH is transmittedmultiple times through a plurality of subframes, a PHICH and a UL grantcorresponding to PUSCH transmission may be present in differentsubframes.

Table 4 shows a UAI (Unlink Association Index) (k) for PUSCHtransmission in LTE(-A). Table 4 shows spacing between a DL subframefrom which a PHICH/UL grant is detected and a UL subframe relating tothe DL subframe. Specifically, when a PHICH/UL grant is detected from asubframe n, the UE can transmit a PUSCH in a subframe n+k.

TABLE 4 TDD UL-DL subframe number n Configuration 0 1 2 3 4 5 6 7 8 9 04 6 4 6 1 6 4 6 4 2 4 4 3 4 4 4 4 4 4 5 4 6 7 7 7 7 5

FIG. 8 illustrates PUSCH transmission timing when UL-DL configuration #1is configured. In the figure, SF#0 to #9 and SF#10 to #19 respectivelycorrespond to radio frames, and numerals in blocks denote UL subframesrelating to DL subframes. For example, a PUSCH corresponding to PHICH/ULgrant of SF#6 is transmitted in SF#6+6(=SF#12) and a PUSCH correspondingto a PHICH/UL grant of SF#14 is transmitted in SF#14+4(=SF#18).

FIGS. 9 and 10 illustrate PUSCH-PHICH/UL grant timing. A PHICH is usedto transmit DL ACK/NACK. Here, DL ACK/NACK means ACK/NACK transmitted ondownlink as a response to UL data (e.g. PUSCH).

Referring to FIG. 9, the UE transmits a PUSCH signal to the BS (S902).Here, the PUSCH signal is used to transmit one or a plurality of (e.g.2) TBs according to transmission mode. The BS can transmit ACK/NACK as aresponse to PUSCH transmission through a PHICH after k subframes viaprocesses for ACK/NACK transmission (e.g. ACK/NACK generation, ACK/NACKresource allocation, etc.) (S904). ACK/NACK includes acknowledgementinformation about the PUSCH signal of step S902. When a response toPUSCH transmission is NACK, the BS can transmit a UL grant PDCCH forPUSCH retransmission to the UE after k subframe (S904). The presentembodiment is based on the assumption that a normal HARQ operation inwhich a PUSCH is transmitted once is performed. In this case, a PHICHand UL grant used for PUSCH transmission can be transmitted in the samesubframe. In case of subframe bundling, however, the PHICH and UL grantused for PUSCH transmission can be transmitted in different subframes.

Table 5 shows a UAI for PHICH/UL grant transmission in LTE(-A). Table 5shows spacing between a DL subframe in which a PHICH/UL grant is presentand a UL subframe relating to the DL subframe. Specifically, a PHICH/ULgrant of a subframe i corresponds to PUSCH transmission through asubframe i−k.

TABLE 5 TDD UL-DL subframe number i Configuration 0 1 2 3 4 5 6 7 8 9 07 4 7 4 1 4 6 4 6 2 6 6 3 6 6 6 4 6 6 5 6 6 6 4 7 4 6

FIG. 10 illustrates PHICH/UL grant transmission timing when UL-DLconfiguration #1 is configured. In the figure, SF#0 to #9 and SF#10 to#19 respectively correspond to radio frames, and numerals in blocksdenote DL subframes relating to UL subframes. For example, a PHICH/ULgrant corresponding to a PUSCH of SF#2 is transmitted in SF#2+4(=SF#6)and a PHICH/UL grant corresponding to a PUSCH of SF#8 is transmitted inSF#8+6(=SF#14).

PHICH resource allocation will now be described. When a PUSCH istransmitted in subframe #n, the UE determines a PHICH resourcecorresponding to the PUSCH in subframe #(n+kPHICH). In case of FDD,kPHICH has a fixed value (e.g. 4). In case of TDD, kPHICH has a valuedepending on UL-DL configuration. Table 6 shows kPHICH for TDD isequivalent to Table 5.

TABLE 6 TDD UL-DL UL subframe index n Configuration 0 1 2 3 4 5 6 7 8 90 4 7 6 4 7 6 1 4 6 4 6 2 6 6 3 6 6 6 4 6 6 5 6 6 4 6 6 4 7

A PHICH resource is provided by [PHICH group index, orthogonal sequenceindex]. The PHICH group index and the orthogonal sequence index aredetermined using (i) a lowest PRB index used for PUSCH transmission and(ii) a 3-bit field value for DMRS (Demodulation Reference Signal) cyclicshift. Here, (i) and (ii) are indicated by a UL grant PDCCH.

A description will be given of a HARQ process. The UE executes aplurality of parallel HARQ processes for UL transmission. The pluralityof parallel HARQ processes is used to continuously perform ULtransmission while the UE waits for HARQ feedback representing whetherprevious UL transmission has been successful or not. Each HARQ processrelates to a HARQ buffer of a MAC (Medium Access Control) layer. EachHARQ process manages the number of transmissions of a MAC PDU (PhysicalData Unit) in the buffer, HARQ feedback for the MAC PDU in the buffer,and a state parameter regarding a current redundancy version.

In case of LTE(-A) FDD, the number of UL HARQ processes for non-subframebundling operation (i.e. normal HARQ operation) is 8. In case of LTE(-A)TDD, the number of UL HARQ processes and HARQ RTT (Round Trip Time) areconfigured differently according to DL-UL configurations because thenumber of UL subframes depends on UL-DL configuration. Here, the HARQRTT may be a time interval (in the unit of SF or ms, for example)between a time when a UL grant is received and a time when a PHICH(corresponding to the UL grant) is received through transmission of aPUSCH (corresponding the UL grant) or a time interval between a PUSCHtransmission time and a PUSCH retransmission time.

The number of UL HARQ processes varies. When subframe bundling isapplied, a bundle of PUSCHs configured of 4 contiguous UL subframes istransmitted in FDD and TDD. Accordingly, a HARQ operation/process whensubframe bundling is applied is different from the normal HARQoperation/process.

Table 8 shows the number of synchronous UL HARQ processes and HARQ RTTin TDD. When the UL HARQ RTT is 10 [SFs or ms] (UL-DL configurations #1,#2, #3, #4 and #5), one UL HARQ process uses one fixed UL SF timing.When the UL HARQ RTT does not correspond to 10 [SFs or ms] (UL-DLconfigurations #0 and #6), one UL HARQ process uses a plurality of UL SFtimings (instead of one fixed UL SF timing) while hopping. For example,in case of UL-DL configuration #6, PUSCH transmission timings in one ULHARQ process are: SF #2: PUSCH=>SF #13: PUSCH (RTT: 11 SFs)=>SF #24:PUSCH (RTT: 11 SFs)=>SF #37: PUSCH (RTT: 13 SFs)=>SF #48: PUSCH (RTT: 11SFs)=>SF #52: PUSCH (RTT: 14 SFs).

TABLE 8 Number of HARQ UL-DL Number of processes for normalconfiguration UL SFs HARQ operation HARQ RTT 0 6 7 11 or 13 1 4 4 10 2 22 10 3 3 3 10 4 2 2 10 5 1 1 10 6 5 6 11 or 13 or 14

In case of TDD UL-DL configurations #1 to #6 and normal HARQ operation,the UE transmits a corresponding PUSCH signal in subframe n+k (refer toTable 5) according to UL grant PDCCH and/or PHICH information upondetection of the UL grant PDCCH and/or PHICH information in subframe n.

In case of TDD UL-DL configuration #0 and the normal HARQ operation,when a UL DCI grant PDCCH and/or a PHICH are detected from subframe n,PUSCH transmission timing of the UE is varied according to conditions.When the MSB (Most Significant bit) of a UL index in DCI is 1 or thePHICH is received through a resource corresponding to I_(PHICH)=0 insubframe #0 or #5, the UE transmits the corresponding PUSCH signal insubframe n+k (refer to Table 5). When the LSB (Least Significant bit) ofthe UL index in the DCI is 1, the PHICH is received through a resourcecorresponding to I_(PHICH)=1 in subframe #0 or #5, or the PHICH isreceived in subframe #1 or #6, UE transmits the corresponding PUSCHsignal in subframe n+7. When both the MSB and LSB in the DCI are set,the UE transmits the corresponding PUSCH signal in subframe n+k (referto Table 5) and subframe n+7.

FIG. 11 illustrates a synchronous UL HARQ process when UL-DLconfiguration #1 is configured. Numerals in blocks denote UL HARQprocess numbers. The synchronous UL HARQ process shown in FIG. 11corresponds to a normal HARQ process. Referring to FIG. 11, HARQ process#1 involves SF#2, SF#6, SF#12 and SF#16. For example, if an initialPUSCH signal (e.g. RV=0) is transmitted in SF#2, a UL grant PDCCH and/ora PHICH corresponding to the PUSCH signal can be received in SF#6 and a(retransmission) PUSCH signal (e.g. RV=2) corresponding to the initialPUSCH signal can be transmitted in SF#12. Accordingly, 4 UL HARQprocesses having an RTT (Round Trip Time) of 10 SFs (or 10 ms) arepresent in case of UL-DL configuration #1.

Transmit Power Control

Various parameters are used to control UL transmit power of a UE. Theseparameters may be divided into open loop power control (OLPC) parametersand closed loop power control (CLPC) parameters. OLPC may be viewed as afactor for controlling power by estimating and compensating attenuationof a DL signal from a serving cell (or a serving base station) to whichthe UE belongs. For example, when the distance from the UE to theserving cell increases, and thus attenuation of the DL signal isworsened, the UL transmit power may be controlled such that the ULtransmit power increases. CLPC is used to control UL power by allowingthe base station to directly deliver information (e.g., a transmit powercontrol (TPC) command) which is needed to adjust the UL transmit power.UL transmit power control is performed by considering OLPC and CLPCtogether.

As a specific example, determination of PUSCH transmit power for PUSCHtransmission of a UE will be discussed below. Equation 1 given below isused to determine the transmit power of the UE when PUSCH and PUCCH arenot transmitted simultaneously in subframe #i of the serving cell c, butonly PUSCH is transmitted.

$\begin{matrix}{{P_{{PUSCH},c}(i)} = {\min {\begin{Bmatrix}{{P_{{CMAX},c}(i)},} \\\begin{matrix}{{10\; {\log_{10}\left( {M_{{PUSCH},c}(i)} \right)}} + {P_{{O\_ {PUSCH}},c}(j)} +} \\{{{\alpha_{c}(j)} \cdot {PL}_{c}} + {\Delta_{{TF},c}(i)} + {f_{c}(i)}}\end{matrix}\end{Bmatrix}\lbrack{dBm}\rbrack}}} & \left\lbrack {{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$

Next, Equation 2 given below is used to determine PUSCH transmit powerwhen PUCCH and PUSCH are transmitted simultaneously in subframe #i ofthe serving cell c.

$\begin{matrix}{{P_{{PUSCH},c}(i)} = {\min {\begin{Bmatrix}{{10{\log_{10}\left( {{{\hat{P}}_{{CMAX},c}(i)} - {{\hat{P}}_{PUCCH}(i)}} \right)}},} \\\begin{matrix}{{10{\log_{10}\left( {M_{{PUSCH},c}(i)} \right)}} + {P_{{O\_ {PUSCH}},c}(j)} +} \\{{{\alpha_{c}(j)} \cdot {PL}_{c}} + {\Delta_{{TF},c}(i)} + {f_{c}(i)}}\end{matrix}\end{Bmatrix}\lbrack{dBm}\rbrack}}} & \left\lbrack {{Equation}\mspace{14mu} 2} \right\rbrack\end{matrix}$

Parameters described below in relation to Equation 1 and Equation 2determine the UL transmit power of the UE in the serving cell c. Herein,P_(CMAX,c)(i) of Equation 1 denotes the maximum transmittable power ofthe UE in subframe #i, and {circumflex over (P)}_(CMAX,c)(i) of Equation2 denotes a linear value of P_(CMAX,c)(i). In Equation 2, {circumflexover (P)}_(PUCCH) (i) denotes a linear value of P_(PUCCH)(i) (whereinP_(PUCCH)(i) indicates PUCCH transmit power in subframe #i).

In Equation 1, M_(PUSCH,c)(i) is a parameter indicating the bandwidthfor PUSCH resource allocation expressed as the number of valid RBs withrespect to subframe #i. The value of this parameter is allocated by theeNB. P_(O) _(—) _(PUSCH,c)(j) is a parameter configured by a sum of acell-specific nominal component P_(O) _(—) _(NOMINAL) _(—) _(PUSCH,c)(j)provided by a higher layer and a UE-specific component P_(O) _(—) _(UE)_(—) _(PUSCH,c)(j) provided by the higher layer. The value of thisparameter is signaled to the UE by the eNB. For PUSCHtransmission/retransmission corresponding to a dynamically scheduledgrant, j=1. For PUSCH transmission/retransmission corresponding to arandom access response grant, j=2. P_(O) _(—) _(UE) _(—) _(PUSCH,c)(2)=0and P_(O) _(—) _(PRE)+Δ_(PREAMBLE) _(—) _(Msg3). Herein, parameterspreamblelnitialReceivedTargetPower (P_(O) _(—) _(PRE)) and Δ_(PREAMBLE)_(—) _(Msg3) are signaled by a higher layer.

α_(c)(j), which is a path loss compensation factor, is a cell-specificparameter provided by a higher layer and transmitted in 3 bits by a basestation. When j=0 or 1, α_(c)∈{0, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1}. Whenj=2, α_(c)(j)=1. α_(c)(j) is a value signaled to the UE by the basestation.

PL_(c) is an estimate of a downlink path loss (or a signal loss)calculated in dB by the UE, and is expressed asPL_(c)=referenceSignalPower−higher layer filtered RSRP (reference signalreceived power). Herein, the base station may inform the UE ofreferenceSignalPower through a higher layer.

f_(c)(i) is a value indicating a current PUSCH power control adjustmentstate for the subframe #i, and may be expressed as a current absolutevalue or accumulated value. When accumulation is enabled based on aparameter Accumulation-enabled provided from a higher layer, or when aTPC command δ_(PUSCH,c) is included in a PDCCH together with DCI format0 for a serving cell c for which CRC is scrambled as a temporary C-RNTI,an equation f_(c)(i)=f_(c)(i−1)+δ_(PUSCH,c)(i−K_(PUSCH)) is satisfied.δ_(PUSCH,c)(i−K_(PUSCH)) is signalled over the PDCCH in subframei−K_(PUSCH) together with DCI format 0/4 or 3/3A. Herein, f_(c)(0) isthe first value after an accumulated value is reset.

In the LTE standard, the value of K_(PUSCH) is defined as follows.

For FDD, K_(PUSCH) is 4. For TDD UL-DL configurations 0-6, the values ofK_(PUSCH) are given as shown in Table 8 below. For TDD UL-DLconfiguration 0, the least significant bit (LSB) of the UL index is setto 1. When PUSCH transmission is scheduled along with PDCCH of DCIformat 0/4 in subframe 2 or 7, K_(PUSCH)=7. For other PUSCHtransmissions, the values of K_(PUSCH) are given in Table 8.

TABLE 8 TDD UL-DL subframe number i Configuration 0 1 2 3 4 5 6 7 8 9 0— — 6 7 4 — — 6 7 4 1 — — 6 4 — — — 6 4 — 2 — — 4 — — — — 4 — — 3 — — 44 4 — — — — — 4 — — 4 4 — — — — — — 5 — — 4 — — — — — — — 6 — — 7 7 5 —— 7 7 —

Except for the case of discontinuous reception (DRX), the UE attempts todecode a PDCCH of DCI format 0/4 using the C-RNTI of the UE or to decodea DCI format for an SPS C-RNTI and a PDCCH of DCI format 3/3A using theTPC-PUSCH-RNTI of the UE in each subframe. When DCI format 0/4 and DCIformat 3/3A for the serving cell c are detected in the same subframe,the terminal should use δ_(PUSCH,c) provided in DCI format 0/4. For asubframe in which a TPC command decoded for the serving cell c is absentor DRX occurs or a subframe indicated by an index i and not used as a ULsubframe in TDD, δ_(PUSCH,c)=0 dB.

An accumulated value δ_(PUSCH,c) signaled on PDCCH together with DCIformat 0/4 is shown in Table 9 given below. When the PDCCH together withDCI format 0 is validated by SPS activation or the PDCCH is released,δ_(PUSCH,c)=0 dB. An accumulated value δ_(PUSCH,c) signaled on PDCCHtogether with DCI format 3/3A corresponds to a SET1 of Table 9, or aSET2 of Table 10 determined by a TPC-index parameter provided by ahigher layer.

TABLE 9 TPC Command Field in Accumulated Absolute δ_(PUSCH,c) [dB] DCIformat 0/3/4 δ_(PUSCH,c) [dB] only DCI format 0/4 0 −1 −4 1 0 −1 2 1 1 33 4

TABLE 10 TPC Command Field in Accumulated δ_(PUSCH,c) DCI format 3A [dB]0 −1 1 1

When the UE reaches a maximum transmit power P_(CMAX,c)(i) in theserving cell c, a positive TPC command is not accumulated for theserving cell c. On the other hand, when UE reaches a minimum maximumpower, a negative TPC command is not accumulated.

The UE resets accumulation when the value P_(O) _(—) _(UE) _(—)_(PUSCH,c)(j) is changed by a higher layer or the UE receives a randomaccess response message in a primary cell.

If accumulation is not enabled based on the parameterAccumulation-enabled provided from a higher layer, the equationf_(c)(i)=δ_(PUSCH,c)(i−K_(PUSCH)) is satisfied. Herein,δ_(PUSCH,c)(i−K_(PUSCH)) is signaled together with DCI format 0/4 onPDCCH in subframe i−K_(PUSCH).

The value of K_(PUSCH) is given as follows. K_(PUSCH) is 4 for FDD. ForTDD UL-DL configurations 1-6, the values of K_(PUSCH) are given in Table8 below. For TDD UL-DL configuration 0, the least significant bit (LSB)of the UL index is set to 1. When PUSCH transmission is scheduled alongwith PDCCH of DCI format 0/4 in subframe 2 or 7, K_(PUSCH)=7. For theother PUSCH transmissions, the values of K_(PUSCH) are given in Table 8.

The accumulated value δ_(PUSCH,c) signaled on PDCCH together with DCIformat 0/4 is given in Table 9. When the PDCCH together with DCI format0 is validated by SPS activation or the PDCCH is released, δ_(PUSCH,c)=0dB.

For a subframe in which a PDCCH accompanied by a DCI format decoded forthe serving cell c is absent or DRX occurs or a subframe indicated by anindex i but not used as a UL subframe in TDD, f_(c)(i)=f_(c)(i=1).

For two types of f (*) (an accumulated value or a current absolutevalue), the first value is set as follows.

For the serving cell c, if the value P_(O) _(—) _(UE) _(—) _(PUSCH,c) ischanged by a higher layer or if the value P_(O) _(—) _(UE) _(—)_(PUSCH,c) is received by a higher layer, and the serving cell c is asecondary cell, f_(c)(0)=0. Conversely, if the serving cell is a primarycell, f_(c)(0)=ΔP_(rampup)+δ_(msg2), wherein δ_(msg2) is a TPC commandindicated in a random access response, and ΔP_(rampup), provided by ahigher layer, corresponds to a total power ramp-up from the first tolast preambles.

In the related art of the present invention, when the TPC commandoperates in an accumulated mode in UL power control (ULPC), theaccumulated value is set to operate as follows. For the serving cell c,when the value P_(O) _(—) _(UE) _(—) _(PUSCH,c)(j) is changed by ahigher layer or when the UE receives a random access response message ina primary cell, the UE should reset accumulation in the following case.

Equation 3 below is an equation related to ULPC for PUCCH.

$\begin{matrix}{{P_{PUCCH}(i)} = {\min {\begin{Bmatrix}{{P_{{CMAX},c}(i)},} \\\begin{matrix}{P_{0{\_ {PUCCH}}} + {PL}_{c} + {h\left( {n_{CQI},n_{HARQ},n_{SR}} \right)} +} \\{{\Delta_{F\_ {PUCCH}}(F)} + {\Delta_{TxD}\left( F^{\prime} \right)} + {g(i)}}\end{matrix}\end{Bmatrix}\lbrack{dBm}\rbrack}}} & \left\lbrack {{Equation}\mspace{14mu} 3} \right\rbrack\end{matrix}$

In Equation 3, i denotes a subframe index, and c denotes a cell index.If the UE is set by a higher layer to transmit a PUCCH on two antennaports, the value Δ_(T×D)(F′) is provided to the UE by the higher layer.Otherwise, 0 is provided. A parameter described below is a parameter fora serving cell having a cell index c.

Herein, P_(CMAX,c)(i) denotes maximum power that may be transmitted bythe UE, P_(O) _(—) _(PUCCH) denotes a parameter including a sum ofcell-specific parameters and is reported by a base station throughhigher layer signaling, and PL_(c) is an estimate of downlink path loss(or signal loss) calculated in dB by the UE and is expressed asPL_(c)=referenceSignalPower−higher layer filtered RSRP. h(n) has a valuevarying with a PUCCH format, n_(CQI) denotes the number of informationbits for CQI, and n_(HARQ) denotes the number of HARQ bits. Δ_(F) _(—)_(PUCCH)(F) is a relative value with respect to PUCCH format 1a, and isreported by the base station through higher layer signaling as a valuecorresponding to a PUCCH format #F.

g(i) denotes a current PUCCH power control adjustment state of asubframe having an index i. and may be defined

${g(i)} = {{g\left( {i - 1} \right)} + {\sum\limits_{m = 0}^{M - 1}\; {{\delta_{PUCCH}\left( {i - k_{m}} \right)}.}}}$

Herein, δ_(PUCCH) may be assigned a value according to Table 11 or Table12 shown below, and M denotes the number of DL subframes associated withone UL subframe (see Table 3).

h(n_(CQI), n_(HARQ), n_(SR)) is 1 for PUCCH formats 1, la and lb. ForPUCCH format 1b, if more than one serving cell is configured for the UE,

${h\left( {n_{CQI},n_{HARQ},n_{SR}} \right)} = {\frac{\left( {n_{HARQ} - 1} \right)}{2}.}$

Otherwise, h(n_(CQI), n_(HARQ), n_(SR)) is 0. For a normal cyclic prefix(CP) for PUCCH formats 2, 2a, and 2b, h(n_(CQI), n_(HARQ), n_(SR)) maybe expressed by Equation 4 below. For an extended CP for PUCCH format 2,h(n_(CQI), n_(HARQ), n_(SR)) may be expressed by Equation 5 below.

$\begin{matrix}{{h\left( {n_{CQI},n_{HARQ},n_{SR}} \right)} = \left\{ \begin{matrix}{10{\log_{10}\left( \frac{n_{CQI}}{4} \right)}} & {{{if}\mspace{14mu} n_{CQI}} \geq 4} \\0 & {otherwise}\end{matrix} \right.} & \left\lbrack {{Equation}\mspace{14mu} 4} \right\rbrack \\{{h\left( {n_{CQI},n_{HARQ},n_{SR}} \right)} = \left\{ \begin{matrix}{10{\log_{10}\left( \frac{n_{CQI} + n_{HARQ}}{4} \right)}} & {{{{if}\mspace{14mu} n_{CQI}} + n_{HARQ}} \geq 4} \\0 & {otherwise}\end{matrix} \right.} & \left\lbrack {{Equation}\mspace{14mu} 5} \right\rbrack\end{matrix}$

For PUCCH format 3, if the UE transmits HARQ-ACK/NACK or schedulingrequest (SR) with 11 or more bits, h(n_(CQI), n_(HARQ), n_(SR)) may beexpressed by Equation 6 given below. Otherwise, h(n_(CQI), n_(HARQ),n_(SR)) may be expressed by Equation 7 below.

$\begin{matrix}{{h\left( {n_{{CQI},},n_{HARQ},n_{SR}} \right)} = \frac{n_{HARQ} + n_{SR} - 1}{3}} & \left\lbrack {{Equation}\mspace{14mu} 6} \right\rbrack \\{{h\left( {n_{CQI},n_{HARQ},n_{SR}} \right)} = \frac{n_{HARQ} + n_{SR} - 1}{2}} & \left\lbrack {{Equation}\mspace{14mu} 7} \right\rbrack\end{matrix}$

If P_(O) _(—) _(UE) _(—) _(PUCCH) is changed by a higher layer, g(0)=0.Otherwise, g(0)=ΔP_(rampup)+δ_(msg2), wherein δ_(msg2) is a TPC commandindicated in a random access response, and ΔP_(rampup), provided by ahigher layer, corresponds to a total power ramp-up from the first tolast preambles.

When the UE reaches the maximum transmit power P_(CMAX,c)(i) in aprimary cell c, a positive TPC command is not accumulated for theprimary cell c. On the other hand, when the UE reaches the minimumpower, a negative TPC command is not accumulated. The UE resetsaccumulation when the value P_(O) _(—) _(UH) _(—) _(PUCCH) is changed bya higher layer or the UE receives a random access response message(msg2).

Table 11 and Table 12 given below shown values of δ_(PUCCH) in the TPCcommand field in DCI formats.

TABLE 11 TPC Command Field in DCI format 1A/1B/1D/1/2A/2B/2C/2/3δ_(PUCCH) [dB] 0 −1 1 0 2 1 3 3

TABLE 12 TPC Command Field in DCI format 3A δ_(PUCCH) [dB] 0 −1 1 1

Method for Dynamic Resource Allocation and ULPC

The present invention proposes examples for supporting DL-ULinterference management and traffic adaptation (IMTA) as an improvedmethod for switching between uses of DL-UL resources. In particular, thepresent invention provides a method for ULPC in dynamically establishinga DL-UL configuration in TDD.

If dynamic switching between uses of DL-UL resources is not supported,optimum resource distribution may be performed between DL and UL atevery time (or in every subframe) when the sizes of the DL traffic andUL traffic change dynamically.

For example, an FDD system is operated by dividing the frequency bandinto a DL band and a UL band. To implement such dynamic switchingbetween resource uses, an eNB may announce, via a radio resource control(RRC) layer signal, a medium access control (MAC) layer signal, or aphysical (PHY) layer signal, whether a specific band is allocated to DLresources or UL resources at a specific time.

Meanwhile, for the TDD system, the whole subframes may be divided intoUL subframes and DL subframes, and each subframe may be used for ULtransmission of the UE or DL transmission of the eNB. Such UL-DLconfiguration is generally included in system information and providedto the UE. For example, one of the UL-DL configurations shown in Table 1may be semi-statically applied. In addition to UL-DL configurations 0-6defined in Table 1, other UL-DL configurations may be defined. In theTDD system, to implement dynamic switching between resource uses, theeNB may announce, via an RRC layer signal, a MAC layer signal, or a PHYlayer signal, whether a specific subframe is allocated to DL resourcesor UL resources at a specific time.

As described above, in the legacy LTE/LTE-A system, DL resources and ULresources are designated through the system information. The systeminformation is information that should be applied to multiple UEs in acell in common Accordingly, when configurations of a DL resource and aUL resource are dynamically changed/switched, a problem may occur withoperation of legacy UEs (e.g., UEs that cannot support dynamic change ofUL-DL configurations). Accordingly, a method to provide informationabout dynamic resource use switching needs to be defined not only bysignaling for delivering the system information but also by newsignaling. In addition, the method needs to be defined by UE-dedicated(or UE-specific) signaling for UEs currently maintaining connection tothe eNB. Dynamic resource use switch may be indicated using such newsignaling (e.g., in the TDD mode, a UL-DL configuration different fromthe configuration established through the system information isdesignated).

New signaling for supporting the dynamic resource use switch may containinformation related to HARQ. For example, when a relationship between aseries of HARQ timings defined by a scheduling message, a PDSCH/PUSCHtransmission/reception time determined according to the message and acorresponding HARQ-ACK/NACK transmission/reception time is defined as aHARQ timeline, the HARQ timeline may not be correctly retained due todynamic switching of resource uses. To prevent this problem, the newsignaling for supporting dynamic switching of resource uses may containinformation about HARQ timeline configuration capable of correctlyretaining the HARQ timeline even if dynamic switching of resource usesis applied. For example, for the TDD system, such HARQ timelineconfiguration information may be given as a UL-DL configuration (e.g.,one of the UL-DL configurations in Table 1) that is referenced when theDL HARQ and/or UL HARQ timeline is defined.

A UE accesing a system supporting the dynamic switch of resource usesmay receive various kinds of information about the resourceconfiguration. For example, in TDD, a UE may acquire at least one of thefollowing configuration signaling 1 to 4 at a specific time.

Configuration signaling 1: A UL-DL configuration indicated by the systeminformation.

Configuration signaling 2: A UL-DL configuration delivered throughsignaling separate from the system information signaling to indicate useof each subframe.

Configuration signaling 3: A UL-DL configuration delivered to define aDL HARQ timeline (i.e., when to transmit UL HARQ-ACK for a PDSCHreceived at a specific time).

Configuration signaling 4: A UL-DL configuration delivered to define aUL HARQ timeline (i.e., when to transmit a PUSCH for a UL grant receivedat a specific time and when to receive a PHICH for the PUSCH transmittedat a specific time).

A configuration for dynamic switching of resource uses provided byConfiguration signaling 2, 3 or 4 may be understood as temporarilyoverriding the configuration of the system information provided byConfiguration signaling 1.

Once the UE accesses an eNB supporting dynamic switching of resourceuses, it is advantageous for the eNB to designate as many UL subframes(UL SFs) as possible through the system information. This is becausethere are limitations on dynamically switching a subframe set as a DLsubframe (DL SF) in the system information to a UL SF, compared todynamically switching a subframe set as a UL SF in the systeminformation to a DL SF. Specifically, legacy UEs operate on theassumption that a cell-specific reference signal (CRS) transmitted fromthe base station will be received in a subframe designated as a DL SF inthe system information. However, if this subframe is set as a UL SF bydynamic switching of resource uses, the CRS is not transmitted, and thusa large error may occur in CSI generation and/or data demodulation,which the legacy UEs perform based on the CRS. Accordingly, it ispreferably for the eNB to designate as many UL SFs as possible throughthe system information and to dynamically switch some of the UL SFs toDL SFs when DL traffic increases.

In an example of the TDD system operating according to the principledescribed above, while the UE is informed that UL-DL configuration #0 ofTable 1 is applied at a specific time according to the systeminformation, the actual resource use in each subframe may be indicatedto conform to UL-DL configuration #1. In addition, it may be indicatedthat UL-DL configuration #2 is applied as a reference of a DL HARQtimeline. If a configuration having a larger number of DL SFs than thenumber of UL SFs is taken as a reference of the DL HARQ timeline asabove, the DL HARQ timeline is very likely to be retained even ifdynamic switching of resource uses is performed. In addition, it may beindicated that UL-DL configuration #0 is applied as the reference of ULHARQ timeline. If a configuration having a larger number of UL SFs thanthe number of DL SFs is taken as a reference of the UL HARQ timeline asabove, the UL HARQ timeline is very likely to be retained even ifdynamic switching of resource uses is performed.

In an environment in which the dynamic switching of resource uses isapplicable, the conventional UL transmit power control method for the UEmay cause many problems since it does not consider dynamic switching ofresource uses. When it is assumed that a subframe set as a DL SF by thesystem information is set as an UL SF by dynamic switching of resourceuses and UL transmission is performed in the subframe, the subframe mayhave an interference environment significantly different from that of anormal UL SF as the subframe is used as a DL SF in a neighboring cell.In conventional cases, UL transmit power control does not consider theaforementioned situation. Accordingly, if the conventional UL transmitpower control is applied as it is, UL transmission performance may besignificantly lowered.

Accordingly, the present invention proposes a new UL power controlmethod which may be used in an environment in which a power controlscheme needs to be separately aped for each specific UL transmission asin the case where the UE establishes access to a system supportingdynamic switching of resource uses.

Embodiment 1

In this embodiment, a plurality of subframe sets is configured and adifferent power control scheme is applied to each subframe set. Theconfiguration information about the plurality of subframe sets may beprovided to the UE through higher layer (e.g., RRC) signaling. Forexample, conventionally defined subframe set configuration information(e.g., an almost blank subframe (ABS)/normal subframe configured forenhanced inter-cell interference coordination (eICIC)) may be applied orconfiguration based thereon may be established. Alternatively, asignaling scheme for separate use similar to the signaling scheme forthe subframe set configuration may be defined.

Further, configuration for a plurality of subframe sets may form thebasis of applying different UL TPC schemes. For example, when the UEreceives signaling for triggering an aperiodic CSI report in subframe tand transmits an aperiodic CSI feedback to the eNB in response insubframe r, different TPC schemes may be applied depending on a subframeset to which the subframe t or subframe r belongs.

For simplicity, it will be assumed herein below that two differentsubframe sets are configured. However, the scope of the presentinvention is not limited thereto. Configuring three or more subframesets is also within the scope of the present invention.

The two different subframe sets proposed in the present invention willbe referred to as “SF Set 0” and “SF Set 1”. SF Set 0 and SF Set 1 maybe defined using an L-bit subframe bitmap. The value of L may bedetermined according to a periodicity of the subframe set configuration.For example, L may be set to 40 in FDD and set to 60 or 70 in TDDdepending on the UL-DL configuration, as in the conventional ABSconfiguration scheme, but embodiments of the present invention are notlimited thereto.

The proposed multiple subframe sets may be configured according to asubframe attribute. For example, one of SF Set 0 and SF Set 1 may bedefined as a set including subframes whose purpose of use is staticallyset (i.e., “Static SFs”), and the other may be defined as a setincluding subframes whose purpose of use is flexibly set (i.e.,“Flexible SFs”).

Specifically, the static SFs may refer to SFs such as conventional SFsto which dynamic switching of resource uses is not applied (for example,SFs for which DL or UL use set by the system information is constantlyretained) as in the case of SF Set 0 of FIG. 12. The flexible SFs mayrefer to SFs to which dynamic switching of resource uses is applied (orapplicable) as in the case of SF Set 1 of FIG. 12.

As shown in FIG. 12, dynamic switch of resource uses may be applied in aserving cell and/or neighbor cell. For example, SF Set 1 includes SF#(n+3), #(n+4), #(n+8), #(n+9), . . . . These subframes may be used asUL resources as originally intended (i.e., as configured through thesystem information) in the serving cell, but may be used as DL resourcesin the neighbor cell according to dynamic switching of resource uses.

In flexible SFs such as SFs of SF Set 1, the interference environmentmay significantly change during UL transmission of the UE unlike in thestatic SFs, and thus a separate UL power control scheme different fromthe UL power control scheme applied in the static SFs is required.

In the example of FIG. 12, with UL-DL configuration #0 (i.e.,DSUUUDSUUU) configured by Cell A (i.e., a serving cell) and Cell B (aneighbor cell) through SIB, Cell B dynamically switches SFscorresponding to indexes #(n+3), #(n+4), #(n+8), #(n+9), . . . to DLSFs.

In this case, Cell A configures SF Set 0 and SF Set 1 for UEs belongingto Cell A as illustrated in FIG. 12, and cause different power controlschemes to be applied to the SF Sets respectively. If inter-cellcoordination is possible, when a specific cell applies dynamic switchingof resource uses, neighbor cells may properly configure SF Sets inconsideration of the dynamic switching. Alternatively, a pattern for SFSet configuration may be predefined between cells and the dynamicswitching of resource uses may be pre-agreed to be applied only in aspecific SF Set (e.g., SF Set 1 in FIG. 12).

As described above regarding the TPC operation with reference toEquations 1 to 7 and Tables 8 to 12, the current LTE/LTE-A standarddefines a TPC field contained in DL-related DCI (e.g., DCI formats 1,1A, 1B, 1D, 2, 2A, 2B, 2C, and 2D) to be applied as a CLPC TPC commandfor a PUCCH on which ACK/NACK for a PDSCH scheduled by the DCI istransmitted, and defines a TPC field contained in UL-related DCI (e.g.,DCI formats 0 and 4) to be applied as a CLPC TPC command for a PUSCHscheduled by the DCI. That is, the power control (PC) process for PUCCHand the PC process for PUSCH operate independently and have a CLPCstructure in which the processes are separately accumulated by acorresponding TPC command.

In this invention, application of a separate (or independent) PUSCH PCprocess distinguished from the conventional PUSCH PC process isproposed. The separate PUSCH PC process newly introduced in the presentinvention may be applied to resources (e.g., static SFs of SF Set 0 inFIG. 12) satisfying a predetermined condition.

For example, when the conventional PUSCH PC process is defined tooperate according to Equation 1, the new separate PUSCH PC process maybe defined to apply a separately set value to one or more of parameters(e.g., P_(CMAX,c)(i), M_(PUSCH,c)(i), P_(O) _(—) _(PUSCH,c)(j),α_(c)(j), PL_(c), Δ_(TF,c)(i), f_(c)(i)) of Equation 1 (for example, theseparate set value may be predetermined through RRC signaling).

For example, in Equation 1, two parameters P_(O) _(—) _(PUSCH,c) ⁽⁰⁾(j)and f_(c) ⁽⁰⁾(i) may be separated and separate values thereof may be setthrough higher layer signaling. Herein, x in P_(O) _(—) _(PUSCH,c)^((x))(j) and f_(c) ^((x))(i) is an index (e.g., 0 or 1) of a subframeset and may be understood as a parameter applied to the subframe set.

In this case, f_(c) ⁽⁰⁾(i) for the separate PUSCH PC process may bedefined to be determined based on g(i) used in the PUCCH PC process inEquation 3 (e.g., f_(c) ⁽⁰⁾(i)=g(i)).

Since the PUCCH is a channel for transmitting important uplink controlinformation (UCI) such as SR, HARQ-ACK/NACK and CSI, allowing the PUCCHto be transmitted on a resource (a flexible SF) which is likely to beswitched for DL use may degrade system performance. Accordingly, thePUCCH is preferably transmitted in a static SF. Accordingly, since thePUSCH PC process in the static SF is preferably operatively connected tothe PC process for PUCCH, f_(c) ⁽⁰⁾(i) for a separate PUSCH PC processmay be operatively connected to g(i) (adjusted by the TPC field of theDL-related DCI) in the PUCCH PC process, such that CLPC accumulation issimultaneously applied.

Meanwhile, the conventional PUSCH PC process may be restricted to beapplied only to SF Set 1 (e.g., flexible SFs). In this case, PUSCH TPCmay operate such that parameter f_(c)(i) given by the TPC field of theUL-related DCI as conventionally defined is accumulated independently off_(c) ⁽⁰⁾(i) is applied to SF Set 0 (e.g., static SFs). Alternatively,as in the conventional PUSCH PC process, f_(c)(i) given by the TPC fieldof the UL-related DCI may be defined as parameter f_(c) ⁽¹⁾(i) andtreated as a parameter separate from f_(c) ⁽⁰⁾(i).

It is also proposed that UL-DL configuration established by a higherlayer (e.g., a UL-DL configuration established by ConfigurationSignaling 3 and delivered to define a DL HARQ timeline) be applied indetermining TPC accumulation for PUCCH. That is, it is proposed thatPUCCH TPC be determined according to a UL-DL configuration fordetermining a DL HARQ timeline provided through RRC signaling ratherthan being determined according to a DL-UL configuration provided assystem information. Herein, the DL HARQ timeline may be viewed as a DLHARQ reference configuration. When ACK/NACK for data received in M (M≧1)DL subframes is transmitted in one UL subframe, the M DL subframes maybe referred to as a DL HARQ reference for one UL subframe.

For example, in PUCCH TPC, if a UL-DL configuration for defining DL HARQtimeline is signaled by a higher layer, this may mean that a PUCCH fortransmitting dynamic ACK/NACK is restricted to be transmitted only in SFSet 0 (e.g., static SFs) in which the separate PUCCH PC process isapplied. In other words, for DL HARQ PUCCH TPC, the time to apply TPC ofDL HARQ PUCCH is determined based on a DL HARQ reference configurationdelivered from the higher layer, and therefore TPC command informationto be applied in performing PUCCH transmission may change depending onDL HARQ reference configuration.

Specifically, a specific UL-DL configuration in Table 1 may beestablished as DL HARQ reference configuration information throughhigher layer (e.g., RRC) signaling. The specific UL-DL configuration maybe, for example, one of UL-DL configurations #2, #4 and #5. This isbecause UL-DL configurations #2, #4 and #5 have one or two UL SFs in oneradio frame, and thus number of UL SFs therefor is relatively smallcompared to the number of UL SFs for the other UL-DL configurations.That is, in consideration that a smaller number of UL SFs isadvantageous in maintaining the DL HARQ timeline as described above, oneof UL-DL configurations #2, #4, and #5 having a relatively small numberof UL SFs may be defined as the DL HARQ reference configuration.

Briefly, in an example of the present invention, a downlink associationset index (DASI) K: {k₀, k₁, . . . , k_(M-1)} for PUCCH TPC accumulation(e.g., calculation of g(i)) may be defined to be set according to a DLHARQ reference configuration established by a higher layer.

If given RRC signaling indicates that the DL HARQ referenceconfiguration is UL-DL configuration #2 of Table 1, PUCCH TPCaccumulation

$\left( {{i.e.},{{g(i)} = {{g\left( {i - 1} \right)} + {\sum\limits_{m = 0}^{M - 1}\; {\delta_{PUCCH}\left( {i - k_{m}} \right)}}}}} \right)$

is applied according to DASI K information indicated by a row in Table 3corresponding to UL-DL configuration #2. Specifically, in determiningtransmit power of PUCCH in SF #n by accumulating TPC information in SF#(n—k), if n=2, k=8, 7, 4, 6. And if n=7, k=8, 7, 4, 6.

If given RRC signaling indicates that the DL HARQ referenceconfiguration is UL-DL configuration #4 of Table 1, PUCCH TPCaccumulation

$\left( {{i.e.},{{g(i)} = {{g\left( {i - 1} \right)} + {\sum\limits_{m = 0}^{M - 1}\; {\delta_{PUCCH}\left( {i - k_{m}} \right)}}}}} \right)$

is applied according to DASI K information indicated by a row in Table 3corresponding to UL-DL configuration #4. Specifically, in determiningtransmit power of PUCCH in SF #n by accumulating TPC information in SF#(n−k), if n=2, k=12, 8, 7, 11. And if n=3, k=6, 5, 4, 70.

If given RRC signaling indicates that the DL HARQ referenceconfiguration is UL-DL configuration #5 of Table 1, PUCCH TPCaccumulation

$\left( {{i.e.},{{g(i)} = {{g\left( {i - 1} \right)} + {\sum\limits_{m = 0}^{M - 1}\; {\delta_{PUCCH}\left( {i - k_{m}} \right)}}}}} \right)$

is applied according to DASI K information indicated by a row in Table 3corresponding to UL-DL configuration #5. Specifically, in determiningtransmit power of PUCCH in SF #n by accumulating TPC information in SF#(n−k), if n=2, k=13, 12, 9, 8, 7, 5, 4, 11, 6.

According to the method of determining PUCCH TPC in consideration of theDL HARQ timeline as described above, the DL HARQ timeline may not beconfigured such that PUCCH ACK/NACK is transmitted in all available ULSFs configured for UL use by the system information. Rather, the DL HARQtimeline may be configured such that PUCCH ACK/NACK transmission isperformed only in UL SFs belonging to a specific SF set (e.g., staticSFs) among the available UL SFs, and not performed in UL SFs belongingto the other SF set (e.g., flexible SFs). There may be variousembodiments of configuration of such DL HARQ timeline. Hereinafter,PUCCH ACK/NACK allowed by the DL HARQ timeline having the aforementionedproperty to be transmitted in only UL SFs belonging to a specific SF set(e.g., static SFs) is referred to simply as “SF-set-specific PUCCH A/N”.

The reason for configuring a DL HARQ timeline for “SF-set-specific PUCCHA/N” is that the interference environment for PUCCH transmission is notconstant due to possibility of application of dynamic switching ofresource uses in the neighbor cells in a specific SF set (e.g., flexibleSFs) and thus it may be difficult to control PUCCH power in such anenvironment. Accordingly, by restricting “SF-set-specific PUCCH A/N”transmission to be performed only in UL SFs belonging to a specific SFset (e.g., static SFs) in which the interference environment does notsignificantly change, PUCCH power control may be facilitated andperformance may be ensured.

Meanwhile, configuration of a plurality of SF sets as proposed in thepresent invention may be explicitly signaled by a higher layer, or maybe indirectly (implicitly) determined using information related to aUL-DL configuration established for another use. When the plurality ofSF sets includes SF set 0, SF set 1, . . . , each SF set may beconfigured as follows.

For example, SF Set 0 (e.g., static SFs) may be defined as a set of SFswhich are configured for UL use in a UL-DL configuration that forms thebasis of defining the DL HARQ timeline. Specifically, the UE maybasically have a UL-DL configuration established through the systeminformation (or SIB), or may have a UL-DL configuration establishedthrough UE-dedicated RRC signaling for overriding a configurationestablished in the system information. Hereinafter, a UL-DLconfiguration that the UE should currently apply will be referred to as“actual UL-DL config”. Meanwhile, as described above regardingConfiguration signaling 3, the UE may have a UL-DL configurationdelivered to define the DL HARQ timeline. Hereinafter, thisconfiguration will be referred to as “DL-HARQ UL-DL config”. Forexample, suppose that “actual UL-DL config” is set to UL-DLconfiguration #3 (i.e., DSUUUDDDDD), and “DL-HARQ UL-DL config” is setto UL-DL configuration #5 (i.e., DSUDDDDDDD). In this case, if explicitsignaling for configuration of SF set 0 (e.g., Static SFs) is notseparately given, only SF #n+2 configured for UL use in UL-DLconfiguration #5 may be implicitly determined to belong to SF set 0 withreference to “DL-HARQ UL-DL config”.

Next, for SF set 1 (e.g., flexible SFs), the SFs configured for UL usein the “actual UL-DL config” except UL SFs belong to SF set 0 may bedefined as remaining UL SFs (or a part of the remaining UL SFs). Forexample, suppose that the “actual UL-DL config” is set to UL-DLconfiguration #3 (i.e., DSUUUDDDDD), and the “DL-HARQ UL-DL config” isset to UL-DL configuration #5 (i.e., DSUDDDDDDD). In this case, whenexplicit signaling for configuration of SF set 1 (e.g., flexible SFs) isnot separately given, it may be implicitly determined that {SF #n+3, SF#n+4} other than SF#n+2 belonging to SF Set 0 may be determined tobelong to SF Set 1 among SF #n+2, SF #n+3 and SF #n+4 configured for ULuse in UL-DL configuration #3 which is set as the “actual UL-DL config”.

Additionally, among the SFs configured for UL use in the “actual UL-DLconfig”, a part of the remaining UL SFs other than UL SFs belonging toSF Set 0 may be configured as SF Set 1, and the others of the remainingUL SFs (or parts of the remaining UL SFs) may be configured as SF Set 2,SF Set 3, and the like. For example, in the example described above,when SF#n+3 and SF#n+4 are the remaining SFs, SF#n+3 may be configuredto belong to SF Set 1, and SF#n+4 may be configured to belong to SF Set2. In this case, signaling or a reference for distinguishing SF set 1,SF set 2, and the like may be required.

In the implicit indication scheme for configuration of a plurality of SFsets, PUCCH ACK/NACK is allowed to be actually transmitted only in SFsconfigured for UL use in the “DL-HARQ UL-DL config” even if separatesignaling is not given. Accordingly, configuring these SFs as static SFsmay prevent signaling overhead and facilitate application ofsubframe-set-specific power control proposed in the present invention.

In addition, since the SFs exemplarily configured as SF set 1 (e.g.,flexible SFs) are dynamically switchable between UL and DL, a separatePUSCH PC process may be applied when the UE transmits PUSCH in theseSFs.

Further, the implicit indication scheme for configuration of a pluralityof SF sets is not limited to the SF-set-specific power control schemeproposed in the present invention, and may be utilized forSF-set-specific operations for SF sets implicitly indicated for otheruses. For example, various operations including SF-set-specificinterference measurement, SF-set-specific restrictive RRM (RadioResource Management) (e.g., RSRP, RSRQ (Reference Signal ReceivedQuality) or the like) and SF-set-specific CSI reporting may be performedaccording to the implicit SF set configuration scheme proposed in thepresent invention.

The aforementioned proposals of the present invention are summarizedbelow.

If a conventional PUSCH PC process applied in a specific SF set (e.g.,SF set 1; flexible SFs) is allowed to be applied in other specific SFsets (e.g., SF set 0; static SFs), degradation of performance may occurdue to the interference environment significantly changing among therespective SF sets. Accordingly, a separate PUSCH PC process may beapplied in each SF set. In addition, by operatively connecting anindependent TPC command to be applied for a specific SF set (e.g., SFset 0; static SFs) to PUCCH TPC rather than to PUSCH TPC, controlchannel overhead resulting from TPC may be minimized For example, PUSCHTPC is preferably set to PUCCH TPC (e.g., f_(c) ⁽⁰⁾(i)=g(i)) for thespecific SF set (e.g., SF set 0; static SFs).

Further, a plurality of PUSCH PC processes may be configured by a higherlayer. A TPC command (e.g., f_(c) ⁽⁰⁾(i)) for the type-0 PUSCH PCprocess may be operatively connected to a TPC command (e.g., g(^(i))adjusted by the TPC field of DL-related DCI) for a specific PUCCH PC(e.g., f_(c) ⁽⁰⁾(i)=g(i)). Thereby, the PUCCH PC process and the PUSCHPC process may simultaneously perform CLPC accumulation. For a TPCparameter (e.g., f_(c) ⁽⁰⁾(i)) for the type-1 PUSCH PC process, thecorresponding command may not be operatively connected to a TPC commandfor PUCCH PC, and CLPC accumulation may be performed through the TPCfield of a specific UL-related DCI as in the conventional cases. For aTPC parameter (e.g., f_(c) ⁽²⁾(i)) for the type-2 PUSCH PC process, aspecific tpc-Index and specific TPC-PUSCH-RNTI may be separatelypre-configured through RRC signaling, and CLPC accumulation may beperformed through DCI 3/3A. The plurality of PUSCH PC processes mayinclude one or more PUSCH PC processes of the same type.

In addition, in each PUSCH PC process, at least one of parameters{P_(CMAX,c)(i), M_(PUSCH,c)(i), P_(O) _(—) _(PUSCH,c)(j), α_(c)(j),PL_(c), Δ_(TF,c)(i), f_(c)(i)} may be separated and pre-configuredthrough RRC signaling.

Embodiment 2

As a PUSCH power control method proposed in the present invention, PUSCHPC processes may be divided according to SF sets, and a TPC command foreach PUSCH PC process is operated by the TPC field which is given when aUL grant is received in the corresponding SF set. Specifically, the TPCfield may be applied only to TPC accumulation for a PUSCH transmitted inan SF belonging to an SF set in which a UL grant is received. In otherwords, a TPC command included in DCI format 0/4/3/3A may be applied onlyto SFs associated with an SF in which DCI format 0/4/3/3A has beenreceived. Hereinafter, this method will be referred to as Rule A.

For example, if a UL grant accompanied by a TPC field is received in anSF belonging to a specific SF set (e.g., SF set 0; static SFs), the UEadjusts power by applying a corresponding TPC command only to CLPCaccumulation of a PUSCH PC process associated with the specific SF set(e.g., SF set 0; static SFs), and performs PUSCH transmission for whichtransmit power is determined If a UL grant accompanied by a TPC field isreceived in an SF of an SF set (e.g., SF set 1; flexible SFs) differentfrom the specific SF set, the UE adjusts power by applying acorresponding TPC command only to CLPC accumulation of a PUSCH PCprocess associated with the SF set (e.g., SF set 1; flexible SFs), andperforms PUSCH transmission for which transmit power is determined.

For example, for a serving cell c, suppose that TPC of a PUSCH PCprocess applied only to SF set 1 is f_(c) ⁽¹⁾(i), and TPC of a PUSCH PCprocess applied only to SF set 2 is f_(c) ⁽²⁾(i).

If TPC accumulation is enabled, f_(c) ^((x))(i)=f_(c)^((x))(i−1)+δ_(PUSCH,c)(i−K_(PUSCH)). Herein, if a UL grantcorresponding to PUSCH transmission in SF #i or SF #j in which DCIformat 3/3A is received belongs to SF set 1, x=1. If a UL grantcorresponding to PUSCH transmission in SF #i or SF index j in which DCIformat 3/3A is received belongs to SF set 2, x=2. In contrast with theconventional TPC accumulation, the UE may determine an SF set includingSF #j in which a UL grant containing scheduling information about PUSCHtransmission in SF #i is received (or DCI format 3/3A containing a TPCcommand applied to PUSCH transmission in SF #i is received), and thendetermine the value of x in f_(c) ^((x))(i) according to thedetermination. Thereby, the UE may determine a PUSCH PC process forwhich TPC accumulation should be performed among multiple PUSCH PCprocesses.

If TPC accumulation is not enabled, f_(c)^((x))(i)=δ_(PUSCH,c)(i−K_(PUSCH)). Herein, if a UL grant correspondingto PUSCH transmission in SF #i or SF #j in which DCI format 3/3A isreceived belongs to SF set 1, x=1. If a UL grant corresponding to PUSCHtransmission in SF #i or SF #j in which DCI format 3/3A is receivedbelongs to SF set 2, x=2. In contrast with the conventional TPCaccumulation, the UE may determine which SF set includes SF #j in whichthe UL grant containing scheduling information about PUSCH transmissionin SF #i is received (or DCI format 3/3A containing a TPC commandapplied to PUSCH transmission in SF #i is received), and then determinethe value of x in f_(c) ^((x))(i) according to the determination.Thereby, the UE may determine a PUSCH PC process for which TPCaccumulation should be performed among multiple PUSCH PC processes.

Embodiment 3

As another PUSCH power control method proposed in the present invention,PUSCH PC processes may be divided according to SF sets, and a TPC fieldcontained in a UL grant (e.g., DCI format 0 or 4) received in SF #n maybe used only for TPC accumulation of a PUSCH PC process associated withan SF set to which a PUSCH transmission SF (e.g., SF #n+k) scheduled bythe UL grant belongs. Alternatively, a TPC field contained in DCI format3/3A received in SF #n may be used only for TPC accumulation of a PUSCHPC process associated with an SF set including an SF (e.g., SF #n+k) inwhich PUSCH transmission subjected to the TPC field is performed.Specifically, depending on an SF set in which a PUSCH scheduled by theUL grant (or a PUSCH to which the TPC command of DCI format 3/3A isapplied) is transmitted, the TPC field may be applied only to TPCaccumulation for the PUSCH transmitted in an SF belonging to the SF set.In other words, a TPC command contained in DCI format 0/4/3/3A may beapplied only to SFs associated with a PUSCH-transmission SF.Hereinafter, this method will be referred to as Rule B.

For example, if a UL grant for a PUSCH to be transmitted is receivedalong with a TPC field (or DCI 3/3A containing a TPC field for the PUSCHis received) in an SF belonging to a specific SF set (e.g., SF set 0;static SFs), the UE adjusts power by applying a corresponding TPCcommand only to CLPC accumulation of a PUSCH PC process associated withthe specific SF set (e.g., SF set 0; static SFs), and performs PUSCHtransmission for which transmit power is determined. If a UL grant for aPUSCH to be transmitted is received along with a TPC field (or DCI 3/3Aincluding a TPC field for the PUSCH is received) in an SF of an SF set(e.g., SF set 1; flexible SFs) different from the specific SF set, theUE adjusts power by applying a corresponding TPC command only to CLPCaccumulation of a PUSCH PC process associated with the SF set (e.g., SFset 1; flexible SFs), and performs PUSCH transmission for which transmitpower is correspondingly determined.

For example, for a serving cell c, suppose that TPC of a PUSCH PCprocess applied only to SF set 1 is f_(c) ⁽¹⁾(i), and TPC of a PUSCH PCprocess applied only to SF set 2 is f_(c) ⁽²⁾(i).

If TPC accumulation is enabled, f_(c) ^((x))(i)=f_(c)^((x))(i−1)+δ_(PUSCH,c)(i−K_(PUSCH)). Herein, if SF #i in which a PUSCHis transmitted belongs to SF set 1, x=1. If SF #i in which a PUSCH istransmitted belongs to SF set 2, x=2. In contrast with the conventionalTPC accumulation, the UE may determine an SF set including SF #i inwhich the PUSCH is transmitted, and then determine the value of x inf_(c) ^((x))(i) according to the determination. Thereby, the UE maydetermine a PUSCH PC process for which TPC accumulation should beperformed among multiple PUSCH PC processes.

If TPC accumulation is not enabled, f_(c)^((x))(i)=δ_(PUSCH,c)(i−K_(PUSCH)). Herein, if SF #i in which a PUSCH istransmitted belongs to SF set 1, x=1. If SF #i in which a PUSCH istransmitted belongs to SF set 2, x=2. In contrast with the conventionalTPC accumulation, the UE may determine an SF set including SF #i inwhich the PUSCH is transmitted, and then determine the value of x inf_(c) ^((x))(i) according to the determination. Thereby, the UE maydetermine a PUSCH PC process for which TPC accumulation should beperformed among multiple PUSCH PC processes.

Embodiment 4

In this embodiment, description will be given of a UL TPC method whichis used when PUSCH transmission in multiple SFs is scheduled by one ULgrant.

For example, if UL-DL configuration #0 (i.e., DSUUUDSUUU) isestablished, and an UL index field is contained in UL-related DCI (e.g.,DCI format 0/4) detected in SF #n and is set to 11, PUSCH transmissionaccording to UL grant may be performed in both SF#n+k and SF#n+7. Inthis case, at least one of various rules (Rule 1 to Rule 8) describedbelow may be applied to process the TPC field contained in theUL-related DCI detected in SF #n.

First, if the plurality of SFs belongs to the same SF set, and the SFset is associated with only one PUSCH PC process, one TPC commandcontained in the UL-related DCI may be applied to CLPC accumulation ofthe PUSCH PC process. The rules described below relate to applying oneTPC command contained in the TPC command to a PUSCH PC process when theSFs belong to different SF sets, and a separate PUSCH PC process isassociated with each SF set.

According to Rule 1, CLPC accumulation according to the TPC is appliedto all PUSCH PC processes associated with at least one SF of a pluralityof SFs in which PUSCH is scheduled in order to adjust power for thePUSCH PC processes and perform PUSCH transmission based on the adjustedpower. If the SFs belong to different SF sets, and a separate PUSCH PCprocess is associated with each SF set, one TPC command contained in theUL-related DCI may be applied to CLPC accumulation for the plurality ofPUSCH PC processes simultaneously.

According to Rule 2, CLPC accumulation according to the TPC is appliedonly to a PUSCH PC process associated with one preceding (or leading) SFof a plurality of SFs in which PUSCH is scheduled in order to adjustpower of the PUSCH PC process and perform PUSCH transmission based onthe adjusted power. If the SFs belong to different SF sets, and aseparate PUSCH PC process is associated with each SF set, the TPCcommand contained in the UL-related DCI is applied only to CLPCaccumulation for the PUSCH PC process associated with an SF set to whichthe leading SF belongs, and is not applied to SF sets to which the otherSFs belong.

According to Rule 3, CLPC accumulation according to the TPC is appliedonly to a PUSCH PC process associated with one SF having a lower (orlowest) slot index or subframe index than other SFs of a plurality ofSFs in which PUSCH is scheduled in order to adjust power of the PUSCH PCprocess and perform PUSCH transmission based on the adjusted power. Theslot/subframe index sequentially increases in a radio frame, and thenset back to index 0 at the boundary between radio frames. A lowerslot/subframe index does not always mean that the index is precedingother indexes in time. If the SFs belong to different SF sets, and aseparate PUSCH PC process is associated with each SF set, the TPCcommand contained in the UL-related DCI is applied only to CLPCaccumulation for the PUSCH PC process associated with an SF set to whichthe SF having the lowest slot/subframe index belongs, and is not appliedto SF sets to which the other SFs belong.

According to Rule 4, CLPC accumulation according to the TPC is appliedonly to a PUSCH PC process associated with one SF that comes later (orlatest) in time sequence of a plurality of SFs in which PUSCH isscheduled in order to adjust power of the PUSCH PC process and performPUSCH transmission based on the adjusted power. If the SFs belong todifferent SF sets, and a separate PUSCH PC process is associated witheach SF set, the TPC command contained in the UL-related DCI is appliedonly to CLPC accumulation for the PUSCH PC process associated with an SFset to which the latest SF, and is not applied to SF sets to which theother SFs belong.

According to Rule 5, CLPC accumulation according to the TPC is appliedonly to PUSCH PC process associated with one SF having a higher (orhighest) slot index or subframe index than other SFs of a plurality ofSFs in which PUSCH is scheduled in order to adjust power of the PUSCH PCprocess and perform PUSCH transmission based on the adjusted power. Ifthe SFs belong to different SF sets, and a separate PUSCH PC process isassociated with each SF set, the TPC command contained in the UL-relatedDCI is applied only to CLPC accumulation for the PUSCH PC processassociated with an SF set to which the SF having the highestslot/subframe index, and is not applied to SF sets to which the otherSFs belong.

Rule 6, which is an extension of Rule 2 to Rule 5, is applied to Q (Q>1)SFs.

According to Rule 2′, which is a variant of Rule 2, CLPC accumulationaccording to the TPC is applied to PUSCH PC processes associated with QSFs preceding the other SFs of a plurality of SFs in which PUSCH isscheduled. According to Rule 3′, which is a variant of Rule 3, CLPCaccumulation according to the TPC is applied to PUSCH PC processesassociated with Q SFs having lower slot/subframe indexes than the otherSFs of a plurality of SFs in which PUSCH is scheduled. According to Rule4′, which is a variant of Rule 4, CLPC accumulation according to the TPCis applied to PUSCH PC processes associated with Q SFs that come afterthe other SFs of a plurality of SFs in which PUSCH is scheduled.According to Rule 5′, which is a variant of Rule 5, CLPC accumulationaccording to the TPC is applied to PUSCH PC processes associated with QSFs having higher slot/subframe indexes than the other SFs of aplurality of SFs in which PUSCH is scheduled.

If the Q SFs belong to different SF set, and a separate PUSCH PC processis associated with each SF set, the TPC command contained in theUL-related DCI is applied to CLPC accumulation for the PUSCH PCprocesses associated with SF sets to which Q SFs belong. If the Q SFsbelong to the same SF set, and only one PUSCH PC process is associatedwith the SF set, one TPC command contained in the UL-related DCI may beapplied to CLPC accumulation of the PUSCH PC process.

According to Rule 7, the TPC command is applied to CLPS accumulation fora PUSCH PC process associated with an SF set only if all SFs in whichPUSCH is scheduled belong to the SF set. Otherwise (i.e., if not all theSFs in which PUSCH is scheduled are included in a specific SF set, butthe SFs belong to different SF sets), the TPC command is ignored (i.e.,the command is not applied to any PUSCH PC process).

According to Rule 8, if SFs in which PUSCH is scheduled belong to Q(Q>1) SF sets, the TPC command is applied to CLPC accumulation of PUSCHPC processes associated with the SF sets. Otherwise (i.e., if the SFs inwhich PUSCH is scheduled are included in different SF sets the number ofwhich is greater than Q (Q>1)), the TPC command is ignored (i.e., thecommand is not applied to any PUSCH PC process). Herein, Q may be athreshold limiting the number of SF sets and be preset.

Rule 1 to Rule 8 described above are simply illustrative. One SF or QSFs may be determined among a plurality of SFs in which PUSCH isscheduled, using various methods. For example, the one or Q SFs may beindicated by a relation to other configurations, a predetermined table,or explicit signaling.

For example, if UL-DL configuration #0 (i.e., DSUUUDSUUU) is establishedfor the UE, and the value of the UL index field contained in theUL-related DCI detected by the UE in SF #j is 11, operation of the UEmay be defined based on SF #j as follows.

If the UL-related DCI is detected in SF#0, the value of TPC contained inthe UL-related DCI is y, and the value of the UL index field is 11,PUSCH is scheduled in SF#4 and SF#7 by the UL grant contained in theUL-related DCI. Herein, it is assumed that SF#4 belongs to SF set 1, andSF#7 belongs to SF set 2. According to Table 8, K_(PUSCH)=4 for SF#4.Accordingly, the TPC value y provided in SF#0(=SF#(4−K_(PUSCH))) isapplied to PUSCH transmission in SF#4. Referring to Table 8, K_(PUSCH)=6for SF#7. Accordingly, if a TPC value is provided inSF#1(=SF#(7−K_(PUSCH))), this value may be applied to PUSCH transmissionin SF#7. That is, the TPC value y provided in SF#0 may be applied onlyto f_(c) ⁽¹⁾(i) of SF set 1 associated with SF#4. This operation mayconform to Rule B.

If the UL-related DCI is detected in SF#5, the value of TPC contained inthe UL-related DCI is y, and the value of the UL index field is 11,PUSCH is scheduled in SF#9 and SF#2 by the UL grant contained in theUL-related DCI. Herein, it is assumed that SF#9 belongs to SF set 1, andSF#2 belongs to SF set 2. According to Table 8, K_(PUSCH)=4 for SF#9.Accordingly, the TPC value y provided in SF#5 is applied to PUSCHtransmission in SF#4. Referring to Table 8, K_(PUSCH)=6 for SF#2.Accordingly, if a TPC value is provided in SF#6, this value may beapplied to PUSCH transmission in SF#2. That is, the TPC value y providedin SF#5 may be applied only to f_(c) ⁽¹⁾(i) of SF set 1 associated withSF#9. This operation may conform to Rule B.

If the UL-related DCI is detected in SF#1, the value of TPC contained inthe UL-related DCI is y, and the value of the UL index field is 11,PUSCH is scheduled in SF#7 and SF#8 by the UL grant contained in theUL-related DCI. Herein, it is assumed that SF#7 belongs to SF set 1, andSF#8 belongs to SF set 2. According to Table 8, K_(PUSCH)=6 for SF#7.Accordingly, the TPC value y provided in SF#1 is applied to PUSCHtransmission in SF#7. Referring to Table 8, K_(PUSCH)=7 for SF#8.Accordingly, the TPC value y provided in SF#1 is also applied to PUSCHtransmission in SF#8. That is, the TPC value y provided in SF#1 is alsoapplied to f_(c) ⁽¹⁾(i) of SF set 1 associated with SF#7 and to f_(c)⁽²⁾(i) of SF set 2 associated with SF#8. This operation may conform toRule 1.

If the UL-related DCI is detected in SF#6, the value of TPC contained inthe UL-related DCI is y, and the value of the UL index field is 11,PUSCH is scheduled in SF#2 and SF#3 by the UL grant contained in theUL-related DCI. Herein, it is assumed that SF#2 belongs to SF set 1, andSF#3 belongs to SF set 2. According to Table 8, K_(PUSCH)=6 for SF#2.Accordingly, the TPC value y provided in SF#6 is applied to PUSCHtransmission in SF#2. Referring to Table 8, K_(PUSCH)=7 for SF#3.Accordingly, the TPC value y provided in SF#6 is applied to PUSCHtransmission in SF#3. That is, the TPC value y provided in SF#6 is alsoapplied to f_(c) ⁽¹⁾(i) of SF set 1 associated with SF#2 and to f_(c)⁽²⁾(i) of SF set 2 associated with SF#3. This operation may conform toRule 1.

Hereinafter, a description will be given of an additional example of thepresent invention.

If the UL-related DCI is detected in SF#1, the value of TPC contained inthe UL-related DCI is y, and the value of the UL index field is 11,PUSCH is scheduled in SF#7 and SF#8 by the UL grant contained in theUL-related DCI. Herein, it is assumed that both SF#7 and SF#8 belong tothe same SF set (e.g., SF set 1). In this case, the TPC value y providedin SF#1 may be applied not only to PUSCH transmission in SF#7 but alsoto PUSCH transmission in SF#8. That is, if the previous TPC level is 0,PUSCH transmission is performed with transmit power of level y in SF#7and with transmit power of level 2y in SF#8.

Herein, if only one TPC command is provided for PUSCH transmission inSFs belonging to the same SF set, it may be more appropriate in terms ofaccurately meeting the purpose of the TPC command to maintain PUSCHtransmit power in the corresponding PUSCH PC process until a new TPCcommand (or an additional TPC command) is provided. That is, in theexample given above, if PUSCH is scheduled in SF#7 and SF#8 by theUL-related DCI detected in SF#1, SF#7 and SF#8 included in the same SFset (or subjected to the same PUSCH PC process), and one TPC commandcontained in the UL-related DCI indicates the value y, PUSCHtransmission is performed with transmit power of level y in SF#7.Preferably, PUSCH transmission is also performed with transmit power oflevel y in SF#8 (namely, the TPC command may not be applied to SF#8).

That is, if the TPC command contained in the UL-related DCI detected inan SF is applied to PUSCH transmission in a plurality of SFs in whichPUSCH is scheduled by the UL grant contained in the UL-related DCI, andthe plurality of SFs belongs to the same SF set, the TPC command isapplied to only one SF (e.g., an SF that comes first or last in time) ofthe SFs, and is not applied to the other SFs. Additionally, a rulestating that SFs are consecutive may be applied. This rule may bedefined as Rule 2″, i.e., another variant of Rule 2.

As in the examples described above, the TPC operation that the UE shouldapply in a plurality of PUSCH transmission subframes scheduled by the ULgrant of UL-related DCI may be differently defined depending on asubframe in which the UL-related DCI is received along with the UL indexset to 11 (for example, Rule B, Rule 1, Rule 2 or Rule 2″ is applieddepending on a subframe index in which the UL-related DCI is detectedalong with the UL index set to 11). Application of Rule B, Rule 1, Rule2, and Rule 2″ in the examples given above is simply illustrative. Atleast one of the various proposed rules (Rules A, B, 1, 2, 3, 4, 5, 6,7, and 8) may be differently applied depending on conditions definedbased on the index of a subframe in which the UL-related DCI isdetected/received along with the UL index set to 11.

Embodiment 5

In this embodiment, description will be given of UL operation that isperformed when a TPC command provided by DCI format 0/4 and a TPCcommand provided by DCI format 3/3A are detected in the same subframe.

The legacy LTE/LTE-A system defines that the UE uses δ_(PUSCH,c)provided from DCI format 0/4 if both DCI format 0/4 and DCI format 3/3Afor the serving cell c are detected in the same subframe. That is, UEoperation is defined such that, if the UL-related DCI (i.e., DCI format0/4) and DCI format 3/3A are received/detected together in a specificsubframe with index j, the TPC command for PUSCH applies only a specificTPC value (e.g., y value) indicated by the UL-related DCI, and aspecific TPC value (e.g., z value) indicated through DCI format 3/3A isignored in the subframe with index j.

In the present invention, on the other hand, for a UE meeting apredetermined condition, if a TPC value (e.g., y value) of UL-relatedDCI (i.e., DCI format 0/4) and a TPC value (e.g., z value) of DCI format3/3A are received/detected together in the specific subframe with indexj, both the TPC values y and z may be defined or set to be effectivelyapplied.

Specifically, TPC (particularly, TPC for PUSCH) may apply the TPC valuey contained in DCI format 0/4 detected in subframe j to f_(c) ^((x))(i)in PUSCH transmission subframe i determined according to a rule such asTable 8 (wherein x is determined depending on whether the subframe withindex i in which PUSCH is transmitted belongs to SF set 0 or SF set 1)and also effectively apply the TPC value z contained in DCI format 3/3Adetected in the subframe j to PUSCH transmission subframe k determinedaccording to a rule such as Table 8.

The UE may perform the aforementioned operation when the UE meets thepredetermined condition, which may be defined as including at least oneof the following conditions: an enhanced IMTA (eIMTA) function isactivated or enabled; UL-DL configuration #0 is established; the ULindex field is set to a specific value; the operation isindicated/configured through predetermined signaling (including implicitsignaling or explicit signaling). Herein, activating/enabling the eIMTAfunction may be performed through RRC signaling which indicates that theeIMTA function (e.g., configuration of a maximum of two power control SFsets including the values of P_(O) _(—) _(PUSCH) and/or α, dynamicsignaling for indicating actual UL-DL config, DL (or UL) HARQ referenceconfiguration, etc.) is enabled or disabled. If disabling is signaled,at least one of elements of the eIMTA function may be released. Ifenabling is signaled, at least one of elements of the eIMTA function maybe configured or activated. Establishing UL-DL configuration #0 includesestablishment through the system information (i.e., SIB1) orestablishment by dynamic signaling that overrides the establishment.Setting the UL index field to a specific value may be defined as settingthe UL index to 01 or 10.

As a specific example, suppose that, when UL-DL configuration #0 (i.e.,DSUUUDSUUU) is given, the TPC value of UL-related DCI having the ULindex field set to 01 (or the LSB of the UL index field is set to 1) isy, the TPC value of DCI format 3/3A is z, and the UL-related DCI and DCIformat 3/3A are simultaneously received in SF#0. In this case, PUSCHscheduling occurs only in SF#7, and K_(PUSCH)=7 is applied according tothe rule described just before Table 8. Accordingly, the TPC value yprovided in SF#0 (i.e., SF#(7−K_(PUSCH))) is applied in SF#7.Additionally, the TPC value z of DCI format 3/3A detected in SF#0, whichis not applied to PUSCH scheduling is applied to SF#4.

In addition, for UL-DL configuration #0 (i.e., DSUUUDSUUU), suppose thatthe TPC value of UL-related DCI having the UL index field set to 01 (orthe LSB of the UL index field is set to 1) is y, the TPC value of DCIformat 3/3A is z, and the UL-related DCI and DCI format 3/3A aresimultaneously received in SF#5. In this case, PUSCH scheduling occursonly in SF#2, and K_(PUSCH)=7 is applied according to the rule describedjust before Table 8 is given. Accordingly, the TPC value y provided inSF#5 (i.e., SF#(2−K_(PUSCH))) is applied in SF#2. The TPC value z of DCIformat 3/3A detected in SF#5 is applied to SF#9.

When UL-related DCI and DCI format 3/3A are simultaneously detected inSF#0, suppose that SF#4 belongs to SF set 1 and SF#7 belongs to SF set2. According to a conventionally defined operation, only TPC value y isapplied to SF#7 to determine and apply f_(c) ⁽²⁾(i). On the other hand,no change occurs in f_(c) ⁽¹⁾(i). According to an example of the presentinvention, only TPC value y is applied to SF#7 to determine and applyf_(c) ⁽²⁾(i) and the TPC value z is applied to SF#4 to determine andapply f_(c) ⁽¹⁾(i). As can be seen from this example, PUSCH schedulingis not applied to SF#4, but f_(c) ⁽¹⁾(i) belonging to SF set 1 may beadjusted through DCI format 3/3A separately from (or regardless of)PUSCH scheduling anytime (before or after PUSCH scheduling). Thereby,flexibility of network configuration/indication may be provided.Further, for an eIMTA supporting system to which the present inventionis applicable, power control is applied by dividing SFs into SF set 0,1, 2, . . . in the time domain, and thus flexibility allowing DCIsignaling for providing an independent TPC command to each SF set islowered. According to the proposed method, however, DCI format 3/3A maybe applied to each SF set without being restricted by time(particularly, regardless of whether DCI format 3/3A and the UL-relatedDCI are provided at the same time), and thus the aforementioned problemmay be solved.

Embodiment 6

In this embodiment, additional description will be given of an operationthat is performed depending on whether actual use of SF#i (e.g., DL orUL subframe) considered when a TPC command contained in DCI format 0/4is provided in SF#(i−k) associated with SF#i according to a TPCtimeline.

If a subframe in which the UL grant of DCI format 0/4 performsscheduling is determined to be a DL subframe according to the actualUL-DL config, this means that one resource is configured for DL use, butis used for UL transmission, and therefore a problem may occur. In thiscase, the UL grant, reconfiguration DCI for providing the actual UL-DLconfig, or both may be ignored, in consideration of (conflicting) PDCCH.

Specifically, when one UL grant schedules one PUSCH, the UL grant may beignored if use of PUSCH transmission UL subframe is reset to DL use.Additionally or separately, when one UL grant schedules two PUSCHs, theUL grant may be ignored if at least one of UL subframes in which the twoPUSCHs are transmitted is reconfigured for DL use (or both PUSCHs arereconfigured for DL use).

An indication indicating whether each of UE operations according to theexamples described above is enabled/disabled may be provided through RRCsignaling or MAC signaling.

FIG. 13 is a flowchart illustrating a method for controlling UL transmitpower according to an embodiment of the present invention.

In step S10, a UE may receive information about a UL-DL configurationfrom a base station. This information may be provided through systeminformation (SIB) or as dynamic configuration for overriding the SIB, ormay be configuration information for other uses (e.g., defining a UL orDL HARQ timeline).

In step S20, the UE may receive TPC information from the base station.This information may be provided through UL-related DCI of DCI format0/4 or through DCI format 3/3A or another DCI format.

In step S30, the UE may determine or update TPC for UL transmission(e.g., PUCCH transmission or PUSCH transmission) based on theinformation received in steps S10 and S20.

In step S40, the UE may perform UL signal transmission to the basestation according to the TPC value determined in step S30.

For the method illustrated in FIG. 13, the above-described embodimentsmay be independently applied or two or more thereof may besimultaneously applied, and description of redundant parts is omitted.

While FIG. 13 illustrates operations for the exemplary method in seriesfor simplicity, this is not intended to limit the order in which theoperations are performed. Operations may be performed simultaneously orin a different order if necessary. Further, not all steps illustrated inFIG. 13 are needed to implement the proposed method of the presentinvention.

FIG. 14 is a diagram illustrating a preferred embodiment of a basestation 10 and a user equipment 20 according to the present invention.

Referring to FIG. 14, the base station 10 of the present invention mayinclude reception module 11, a transmission module 12, a processor 13, amemory 14, and a plurality of antennas 15. The plurality of antennas 15mean the base station that supports MIMO transmission and reception. Thereception module 11 may receive various kinds of signals, data andinformation on an uplink from the user equipment. The transmissionmodule 12 may transmit various kinds of signal, data and information ona downlink to the user equipment. The processor 13 may control theoverall operation of the base station 10.

The processor 13 of the base station 10 is configured to determineinformation about UL-DL configuration, TPC information, and the like andprovide the same to a user equipment 20 by controlling the transmissionmodule 12. The processor 13 may also be configured to receive ULtransmission from the user equipment 20 by controlling the receptionmodule 11.

For various kinds of information and UL transmit power control methodsthat the base station 10 configured as above provides to the userequipment 20 to allow the user equipment 20 to control UL transmitpower, one of or a combination of two or more of the examples proposedin the present invention may be applied.

In addition, the processor 13 of the base station 10 performs anoperation for information received by the base station 10, informationto be transmitted to the outside, etc., and the memory 14 may store theoperation processed information for a predetermined time and may bereplaced with an element such as a buffer (not shown).

Referring to FIG. 14, the user equipment 20 of the present invention mayinclude reception module 21, a transmission module 22, a processor 23, amemory 24, and a plurality of antennas 25. The plurality of antennas 25mean the user equipment that supports MIMO transmission and reception.The reception module 21 may receive various kinds of signals, data andinformation on a downlink from the base station. The transmission module22 may transmit various kinds of signal, data and information on anuplink to the base station. The processor 23 may control the overalloperation of the user equipment 20.

The processor 23 of the user equipment 20 may be configured to receiveinformation about UL-DL configuration, TPC information, and the likefrom the base station 10 by controlling the reception module 21. Theprocessor 23 may also be configured to transmit UL transmission to thebase station 10 by controlling the transmission module 22.

For various kinds of information and UL transmit power control methodsthat the user equipment 20 configured as above receives from the basestation 10 to control UL transmit power, one of or a combination of twoor more of the examples proposed in the present invention may beapplied.

In addition, the processor 23 of the user equipment 20 performs anoperation for information received by the user equipment 20, informationto be transmitted to the outside, etc., and the memory 24 may store theoperation processed information for a predetermined time and may bereplaced with an element such as a buffer (not shown).

The details of the aforementioned base station and the aforementioneduser equipment may be configured in such a manner that theaforementioned various embodiments of the present invention mayindependently be applied to the aforementioned base station and theaforementioned user equipment, or two or more embodiments maysimultaneously be applied to the aforementioned base station and theaforementioned user equipment, and repeated description will be omittedfor clarification.

In description of various examples of the present invention given above,the base station has been mainly assumed to be a DL transmission entityor a UL reception entity, and the UE has been mainly assumed to be a DLreception entity or a UL transmission entity. However, the scope of thepresent invention is not limited thereto. For example, the descriptionof the base station may also be applied to a case where a cell, antennaport, antenna port group, RRH, transmission point, reception point,access point, or relay serves as an entity of DL transmission to the UEor an entity of UL reception from the UE. When the relay serves as anentity of DL transmission to the UE or an entity of UL reception fromthe UE or serves as an entity of UL transmission to the base station oran entity of DL reception from the base station, the principle of thepresent invention described above in various embodiments may be equallyapplied.

The embodiments according to the present invention may be implemented byvarious means, for example, hardware, firmware, software, or theircombination.

If the embodiment according to the present invention is implemented byhardware, the embodiment of the present invention may be implemented byone or more application specific integrated circuits (ASICs), digitalsignal processors (DSPs), digital signal processing devices (DSPDs),programmable logic devices (PLDs), field programmable gate arrays(FPGAs), processors, controllers, microcontrollers, microprocessors,etc.

If the embodiment according to the present invention is implemented byfirmware or software, the embodiment of the present invention may beimplemented by a type of a module, a procedure, or a function, whichperforms functions or operations described as above. A software code maybe stored in a memory unit and then may be driven by a processor. Thememory unit may be located inside or outside the processor to transmitand receive data to and from the processor through various means whichare well known.

It will be apparent to those skilled in the art that the presentinvention may be embodied in other specific forms without departing fromthe spirit and essential characteristics of the invention. Thus, theabove embodiments are to be considered in all respects as illustrativeand not restrictive. The scope of the invention should be determined byreasonable interpretation of the appended claims and all change whichcomes within the equivalent scope of the invention are included in thescope of the invention.

Those skilled in the art will appreciate that the present invention maybe carried out in other specific ways than those set forth hereinwithout departing from the spirit and essential characteristics of thepresent invention. The above embodiments are therefore to be construedin all aspects as illustrative and not restrictive. The scope of theinvention should be determined by the appended claims and their legalequivalents, not by the above description, and all changes coming withinthe meaning and equivalency range of the appended claims are intended tobe embraced therein. It is also obvious to those skilled in the art thatclaims that are not explicitly cited in each other in the appendedclaims may be presented in combination as an embodiment of the presentinvention or included as a new claim by a subsequent amendment after theapplication is filed.

INDUSTRIAL APPLICABILITY

The embodiments of the present invention described above are applicableto various mobile communication systems.

1. A method for performing uplink transmit power control by a userequipment in a wireless communication system, the method comprising:receiving configuration information about a plurality of subframe setsfrom a base station; receiving transmit power control (TPC) informationfrom the base station in a subframe #j; and determining a transmit powerfor an uplink channel in a subframe #i based on the TPC information,wherein the TPC information is applied to a power control processassociated with a first subframe set including the subframe #i among thesubframe sets.
 2. The method according to claim 1, wherein the TPCinformation is not applied to a power control process associated with asecond subframe set among the subframe sets.
 3. The method according toclaim 1, wherein the TPC information is contained in downlink controlinformation (DCI) format 0 or DCI format 4 containing uplink grantinformation for scheduling uplink data transmission in the subframe #i.4. The method according to claim 1, wherein the TPC information iscontained in downlink control information (DCI) format 3 or DCI format3A.
 5. The method according to claim 1, wherein association between thesubframe #j and the subframe #i is determined based on uplink-downlink(UL-DL) configuration information provided from the base station.
 6. Themethod according to claim 5, wherein the UL-DL configuration informationis provided through dynamic signaling.
 7. The method according to claim1, wherein the uplink channel is a physical uplink control channel(PUCCH) or physical uplink shared channel (PUSCH).
 8. The methodaccording to claim 1, wherein the wireless communication system is atime division duplex (TDD) system.
 9. A method for receiving an uplinksignal by a base station in a wireless communication system, the methodcomprising: transmitting configuration information about a plurality ofsubframe sets to a user equipment; transmitting transmit power control(TPC) information to the user equipment in a subframe #j; and receivingthe uplink signal from the user equipment on an uplink channel in asubframe #i, wherein a transmit power for the uplink channel in thesubframe #i is determined based on the TPC information, wherein the TPCinformation is applied to a power control process associated with afirst subframe set including the subframe #i among the subframe sets.10. A user equipment for performing uplink transmit power control in awireless communication system, comprising: a transmission module; areception module; and a processor, wherein the processor is configuredto: control the reception module to receive configuration informationabout a plurality of subframe sets from a base station; control thereception module to receive transmit power control (TPC) informationfrom the base station in a subframe #j; and determine a transmit powerfor an uplink channel in a subframe #i based on the TPC information,wherein the TPC information is applied to a power control processassociated with a first subframe set including the subframe #i among thesubframe sets.
 11. A base station for receiving an uplink signal in awireless communication system, comprising: a transmission module; areception module; and a processor, wherein the processor is configuredto: control the transmission module to transmit configurationinformation about a plurality of subframe sets to a user equipment;control the transmission module to transmit transmit power control (TPC)information to the user equipment in a subframe #j; control thereception module to receive the uplink signal from the user equipment onan uplink channel in a subframe #i, wherein a transmit power for theuplink channel in the subframe #i is determined based on the TPCinformation, wherein the TPC information is applied to a power controlprocess associated with a first subframe set including the subframe #iamong the subframe sets.